re PR tree-optimization/19431 (missed optimization with ifs and deferencing)
2007-04-18 Richard Guenther <rguenther@suse.de> PR tree-optimization/19431 PR tree-optimization/21463 * tree-pass.h (pass_phiprop): Declare. * passes.c (init_optimization_passes): New phiprop pass. * tree-ssa-forwprop.c (struct phiprop_d): New structure. (phivn_valid_p): New helper function. (phiprop_insert_phi): Likewise. (propagate_with_phi): Likewise. (tree_ssa_phiprop): New propagator propagating loads through phi nodes if profitable. * gcc.c-torture/execute/20070212-1.c: New testcase. * gcc.c-torture/execute/20070212-2.c: Likewise. * gcc.c-torture/execute/20070212-3.c: Likewise. * gcc.dg/tree-ssa/pr19431.c: Likewise. * gcc.dg/tree-ssa/pr21463.c: Likewise. * g++.dg/tree-ssa/pr21463.C: Likewise. * g++.dg/tree-ssa/pr30738.C: Likewise. From-SVN: r123946
This commit is contained in:
Richard Guenther
Richard Biener
parent
383862e812
commit
3b48ccbc89
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@ -1,3 +1,16 @@
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2007-04-18 Richard Guenther <rguenther@suse.de>
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PR tree-optimization/19431
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PR tree-optimization/21463
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* tree-pass.h (pass_phiprop): Declare.
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* passes.c (init_optimization_passes): New phiprop pass.
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* tree-ssa-forwprop.c (struct phiprop_d): New structure.
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(phivn_valid_p): New helper function.
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(phiprop_insert_phi): Likewise.
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(propagate_with_phi): Likewise.
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(tree_ssa_phiprop): New propagator propagating loads
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through phi nodes if profitable.
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2007-04-18 Dorit Nuzman <dorit@il.ibm.com>
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* tree-vect-analyze.c (process_use): New function.
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@ -524,6 +524,7 @@ init_optimization_passes (void)
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/* Initial scalar cleanups. */
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NEXT_PASS (pass_ccp);
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NEXT_PASS (pass_phiprop);
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NEXT_PASS (pass_fre);
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NEXT_PASS (pass_dce);
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NEXT_PASS (pass_forwprop);
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@ -1,3 +1,15 @@
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2007-04-18 Richard Guenther <rguenther@suse.de>
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PR tree-optimization/19431
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PR tree-optimization/21463
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* gcc.c-torture/execute/20070212-1.c: New testcase.
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* gcc.c-torture/execute/20070212-2.c: Likewise.
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* gcc.c-torture/execute/20070212-3.c: Likewise.
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* gcc.dg/tree-ssa/pr19431.c: Likewise.
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* gcc.dg/tree-ssa/pr21463.c: Likewise.
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* g++.dg/tree-ssa/pr21463.C: Likewise.
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* g++.dg/tree-ssa/pr30738.C: Likewise.
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2007-04-17 Mark Mitchell <mark@codesourcery.com>
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PR c++/31513
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@ -0,0 +1,20 @@
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/* { dg-do compile } */
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/* { dg-options "-O -fdump-tree-phiopt1" } */
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template<class T> static inline const T &ref_max(const T &a, const T &b)
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{ return a<b ? b : a; }
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template<class T> static inline const T &ref_min(const T &a, const T &b)
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{ return a<b ? a : b; }
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template<class T> struct foo_t {
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T a0, a1;
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T bar_ref(const T b, const T c) {
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return ref_max(ref_min(a0, c), ref_min(ref_max(a1, c), b));
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}
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};
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template struct foo_t<int>;
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/* { dg-final { scan-tree-dump-times "MIN_EXPR" 2 "phiopt1" } } */
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/* { dg-final { scan-tree-dump-times "MAX_EXPR" 2 "phiopt1" } } */
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/* { dg-final { cleanup-tree-dump "phiopt1" } } */
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@ -0,0 +1,17 @@
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/* { dg-do compile } */
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/* { dg-options "-O -fdump-tree-phiopt1" } */
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template <class T>
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static inline const T&
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min_ref (const T &x, const T &y)
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{
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return x < y ? x : y;
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}
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int test_min_ref (int x, int y)
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{
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return min_ref (x, y);
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}
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/* { dg-final { scan-tree-dump "MIN_EXPR" "phiopt1" } } */
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/* { dg-final { cleanup-tree-dump "phiopt1" } } */
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@ -0,0 +1,26 @@
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struct f
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{
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int i;
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};
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int g(int i, int c, struct f *ff, int *p)
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{
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int *t;
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if (c)
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t = &i;
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else
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t = &ff->i;
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*p = 0;
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return *t;
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}
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extern void abort(void);
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int main()
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{
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struct f f;
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f.i = 1;
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if (g(5, 0, &f, &f.i) != 0)
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abort ();
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return 0;
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}
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@ -0,0 +1,19 @@
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int f(int k, int i1, int j1)
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{
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int *f1;
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if(k)
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f1 = &i1;
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else
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f1 = &j1;
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i1 = 0;
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return *f1;
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}
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extern void abort (void);
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int main()
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{
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if (f(1, 1, 2) != 0)
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abort ();
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return 0;
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}
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@ -0,0 +1,30 @@
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struct foo { int i; int j; };
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int bar (struct foo *k, int k2, int f, int f2)
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{
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int *p, *q;
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int res;
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if (f)
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p = &k->i;
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else
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p = &k->j;
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res = *p;
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k->i = 1;
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if (f2)
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q = p;
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else
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q = &k2;
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return res + *q;
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}
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extern void abort (void);
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int main()
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{
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struct foo k;
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k.i = 0;
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k.j = 1;
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if (bar (&k, 1, 1, 1) != 1)
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abort ();
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return 0;
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}
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@ -0,0 +1,29 @@
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/* { dg-do compile } */
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/* { dg-options "-O2 -fdump-tree-optimized" } */
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/* We want this optimized as
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<bb 2>:
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if (k != 0) goto <L2>; else goto <L3>;
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<L3>:;
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i1 = j1;
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<L2>:;
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return i1;
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This requires that i1 and j1 are changed into registers after they
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no longer have their address taken. */
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int f(int k, int i1, int j1)
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{
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int *f1;
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if(k)
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f1 = &i1;
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else
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f1 = &j1;
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return *f1;
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}
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/* { dg-final { scan-tree-dump "i1 = j1" "optimized" } } */
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/* { dg-final { scan-tree-dump "return i1;" "optimized" } } */
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/* { dg-final { cleanup-tree-dump "optimized" } } */
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@ -0,0 +1,20 @@
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/* { dg-do compile } */
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/* { dg-options "-O -fdump-tree-phiprop" } */
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struct f
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{
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int i;
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};
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int g(int i, int c, struct f *ff, int g)
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{
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int *t;
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if (c)
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t = &i;
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else
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t = &ff->i;
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return *t;
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}
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/* { dg-final { scan-tree-dump-not "\\*t" "phiprop" } } */
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/* { dg-final { cleanup-tree-dump "phiprop" } } */
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@ -285,6 +285,7 @@ extern struct tree_opt_pass pass_warn_function_return;
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extern struct tree_opt_pass pass_warn_function_noreturn;
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extern struct tree_opt_pass pass_phiopt;
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extern struct tree_opt_pass pass_forwprop;
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extern struct tree_opt_pass pass_phiprop;
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extern struct tree_opt_pass pass_dse;
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extern struct tree_opt_pass pass_nrv;
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extern struct tree_opt_pass pass_mark_used_blocks;
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@ -1059,3 +1059,302 @@ struct tree_opt_pass pass_forwprop = {
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| TODO_verify_ssa, /* todo_flags_finish */
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0 /* letter */
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};
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/* Structure to keep track of the value of a dereferenced PHI result
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and the set of virtual operands used for that dereference. */
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struct phiprop_d
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{
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tree value;
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tree vop_stmt;
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};
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/* Verify if the value recorded for NAME in PHIVN is still valid at
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the start of basic block BB. */
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static bool
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phivn_valid_p (struct phiprop_d *phivn, tree name, basic_block bb)
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{
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tree vop_stmt = phivn[SSA_NAME_VERSION (name)].vop_stmt;
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ssa_op_iter ui;
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tree vuse;
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/* The def stmts of all virtual uses need to be post-dominated
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by bb. */
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FOR_EACH_SSA_TREE_OPERAND (vuse, vop_stmt, ui, SSA_OP_VUSE)
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{
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tree use_stmt;
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imm_use_iterator ui2;
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bool ok = true;
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FOR_EACH_IMM_USE_STMT (use_stmt, ui2, vuse)
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{
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/* If BB does not dominate a VDEF, the value is invalid. */
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if (((TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
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&& !ZERO_SSA_OPERANDS (use_stmt, SSA_OP_VDEF))
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|| TREE_CODE (use_stmt) == PHI_NODE)
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&& !dominated_by_p (CDI_DOMINATORS, bb_for_stmt (use_stmt), bb))
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{
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ok = false;
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BREAK_FROM_IMM_USE_STMT (ui2);
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}
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}
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if (!ok)
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return false;
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}
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return true;
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}
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/* Insert a new phi node for the dereference of PHI at basic_block
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BB with the virtual operands from USE_STMT. */
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static tree
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phiprop_insert_phi (basic_block bb, tree phi, tree use_stmt,
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struct phiprop_d *phivn, size_t n)
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{
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tree res, new_phi;
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edge_iterator ei;
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edge e;
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/* Build a new PHI node to replace the definition of
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the indirect reference lhs. */
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res = GIMPLE_STMT_OPERAND (use_stmt, 0);
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SSA_NAME_DEF_STMT (res) = new_phi = create_phi_node (res, bb);
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/* Add PHI arguments for each edge inserting loads of the
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addressable operands. */
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FOR_EACH_EDGE (e, ei, bb->preds)
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{
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tree old_arg, new_var, tmp;
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old_arg = PHI_ARG_DEF_FROM_EDGE (phi, e);
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while (TREE_CODE (old_arg) == SSA_NAME
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&& (SSA_NAME_VERSION (old_arg) >= n
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|| phivn[SSA_NAME_VERSION (old_arg)].value == NULL_TREE))
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{
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tree def_stmt = SSA_NAME_DEF_STMT (old_arg);
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old_arg = GIMPLE_STMT_OPERAND (def_stmt, 1);
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}
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if (TREE_CODE (old_arg) == SSA_NAME)
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/* Reuse a formely created dereference. */
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new_var = phivn[SSA_NAME_VERSION (old_arg)].value;
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else
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{
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old_arg = TREE_OPERAND (old_arg, 0);
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new_var = create_tmp_var (TREE_TYPE (old_arg), NULL);
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tmp = build2 (GIMPLE_MODIFY_STMT, void_type_node,
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NULL_TREE, unshare_expr (old_arg));
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if (TREE_CODE (TREE_TYPE (old_arg)) == COMPLEX_TYPE
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|| TREE_CODE (TREE_TYPE (old_arg)) == VECTOR_TYPE)
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DECL_GIMPLE_REG_P (new_var) = 1;
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add_referenced_var (new_var);
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new_var = make_ssa_name (new_var, tmp);
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GIMPLE_STMT_OPERAND (tmp, 0) = new_var;
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bsi_insert_on_edge (e, tmp);
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update_stmt (tmp);
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mark_symbols_for_renaming (tmp);
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}
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add_phi_arg (new_phi, new_var, e);
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}
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update_stmt (new_phi);
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return res;
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}
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/* Propagate between the phi node arguments of PHI in BB and phi result
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users. For now this matches
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# p_2 = PHI <&x, &y>
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<Lx>:;
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p_3 = p_2;
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z_2 = *p_3;
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and converts it to
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# z_2 = PHI <x, y>
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<Lx>:;
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Returns true if a transformation was done and edge insertions
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need to be committed. Global data PHIVN and N is used to track
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past transformation results. We need to be especially careful here
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with aliasing issues as we are moving memory reads. */
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static bool
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propagate_with_phi (basic_block bb, tree phi, struct phiprop_d *phivn, size_t n)
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{
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tree ptr = PHI_RESULT (phi);
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tree use_stmt, res = NULL_TREE;
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block_stmt_iterator bsi;
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imm_use_iterator ui;
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use_operand_p arg_p, use;
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ssa_op_iter i;
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bool phi_inserted;
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if (MTAG_P (SSA_NAME_VAR (ptr))
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|| !POINTER_TYPE_P (TREE_TYPE (ptr))
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|| !is_gimple_reg_type (TREE_TYPE (TREE_TYPE (ptr))))
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return false;
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|
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/* Check if we can "cheaply" dereference all phi arguments. */
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FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
|
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{
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tree arg = USE_FROM_PTR (arg_p);
|
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/* Walk the ssa chain until we reach a ssa name we already
|
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created a value for or we reach a definition of the form
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ssa_name_n = &var; */
|
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while (TREE_CODE (arg) == SSA_NAME
|
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&& !SSA_NAME_IS_DEFAULT_DEF (arg)
|
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&& (SSA_NAME_VERSION (arg) >= n
|
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|| phivn[SSA_NAME_VERSION (arg)].value == NULL_TREE))
|
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{
|
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tree def_stmt = SSA_NAME_DEF_STMT (arg);
|
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if (TREE_CODE (def_stmt) != GIMPLE_MODIFY_STMT)
|
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return false;
|
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arg = GIMPLE_STMT_OPERAND (def_stmt, 1);
|
||||
}
|
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if ((TREE_CODE (arg) != ADDR_EXPR
|
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/* Avoid to have to decay *&a to a[0] later. */
|
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|| !is_gimple_reg_type (TREE_TYPE (TREE_OPERAND (arg, 0))))
|
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&& !(TREE_CODE (arg) == SSA_NAME
|
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&& phivn[SSA_NAME_VERSION (arg)].value != NULL_TREE
|
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&& phivn_valid_p (phivn, arg, bb)))
|
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return false;
|
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}
|
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|
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/* Find a dereferencing use. First follow (single use) ssa
|
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copy chains for ptr. */
|
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while (single_imm_use (ptr, &use, &use_stmt)
|
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&& TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
|
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&& GIMPLE_STMT_OPERAND (use_stmt, 1) == ptr
|
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&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME)
|
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ptr = GIMPLE_STMT_OPERAND (use_stmt, 0);
|
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|
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/* Replace the first dereference of *ptr if there is one and if we
|
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can move the loads to the place of the ptr phi node. */
|
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phi_inserted = false;
|
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FOR_EACH_IMM_USE_STMT (use_stmt, ui, ptr)
|
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{
|
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ssa_op_iter ui2;
|
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tree vuse;
|
||||
|
||||
/* Check whether this is a load of *ptr. */
|
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if (!(TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
|
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&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME
|
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&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == INDIRECT_REF
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&& TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 0) == ptr
|
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/* We cannot replace a load that may throw or is volatile. */
|
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&& !tree_can_throw_internal (use_stmt)))
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continue;
|
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|
||||
/* Check if we can move the loads. The def stmts of all virtual uses
|
||||
need to be post-dominated by bb. */
|
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FOR_EACH_SSA_TREE_OPERAND (vuse, use_stmt, ui2, SSA_OP_VUSE)
|
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{
|
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tree def_stmt = SSA_NAME_DEF_STMT (vuse);
|
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if (!SSA_NAME_IS_DEFAULT_DEF (vuse)
|
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&& (bb_for_stmt (def_stmt) == bb
|
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|| !dominated_by_p (CDI_DOMINATORS,
|
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bb, bb_for_stmt (def_stmt))))
|
||||
goto next;
|
||||
}
|
||||
|
||||
/* Found a proper dereference. Insert a phi node if this
|
||||
is the first load transformation. */
|
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if (!phi_inserted)
|
||||
{
|
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res = phiprop_insert_phi (bb, phi, use_stmt, phivn, n);
|
||||
|
||||
/* Remember the value we created for *ptr. */
|
||||
phivn[SSA_NAME_VERSION (ptr)].value = res;
|
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phivn[SSA_NAME_VERSION (ptr)].vop_stmt = use_stmt;
|
||||
|
||||
/* Remove old stmt. The phi is taken care of by DCE, if we
|
||||
want to delete it here we also have to delete all intermediate
|
||||
copies. */
|
||||
bsi = bsi_for_stmt (use_stmt);
|
||||
bsi_remove (&bsi, 0);
|
||||
|
||||
phi_inserted = true;
|
||||
}
|
||||
else
|
||||
{
|
||||
/* Further replacements are easy, just make a copy out of the
|
||||
load. */
|
||||
GIMPLE_STMT_OPERAND (use_stmt, 1) = res;
|
||||
update_stmt (use_stmt);
|
||||
}
|
||||
|
||||
next:;
|
||||
/* Continue searching for a proper dereference. */
|
||||
}
|
||||
|
||||
return phi_inserted;
|
||||
}
|
||||
|
||||
/* Helper walking the dominator tree starting from BB and processing
|
||||
phi nodes with global data PHIVN and N. */
|
||||
|
||||
static bool
|
||||
tree_ssa_phiprop_1 (basic_block bb, struct phiprop_d *phivn, size_t n)
|
||||
{
|
||||
bool did_something = false;
|
||||
basic_block son;
|
||||
tree phi;
|
||||
|
||||
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
|
||||
did_something |= propagate_with_phi (bb, phi, phivn, n);
|
||||
|
||||
for (son = first_dom_son (CDI_DOMINATORS, bb);
|
||||
son;
|
||||
son = next_dom_son (CDI_DOMINATORS, son))
|
||||
did_something |= tree_ssa_phiprop_1 (son, phivn, n);
|
||||
|
||||
return did_something;
|
||||
}
|
||||
|
||||
/* Main entry for phiprop pass. */
|
||||
|
||||
static unsigned int
|
||||
tree_ssa_phiprop (void)
|
||||
{
|
||||
struct phiprop_d *phivn;
|
||||
|
||||
calculate_dominance_info (CDI_DOMINATORS);
|
||||
|
||||
phivn = XCNEWVEC (struct phiprop_d, num_ssa_names);
|
||||
|
||||
if (tree_ssa_phiprop_1 (ENTRY_BLOCK_PTR, phivn, num_ssa_names))
|
||||
bsi_commit_edge_inserts ();
|
||||
|
||||
free (phivn);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static bool
|
||||
gate_phiprop (void)
|
||||
{
|
||||
return 1;
|
||||
}
|
||||
|
||||
struct tree_opt_pass pass_phiprop = {
|
||||
"phiprop", /* name */
|
||||
gate_phiprop, /* gate */
|
||||
tree_ssa_phiprop, /* execute */
|
||||
NULL, /* sub */
|
||||
NULL, /* next */
|
||||
0, /* static_pass_number */
|
||||
TV_TREE_FORWPROP, /* tv_id */
|
||||
PROP_cfg | PROP_ssa, /* properties_required */
|
||||
0, /* properties_provided */
|
||||
0, /* properties_destroyed */
|
||||
0, /* todo_flags_start */
|
||||
TODO_dump_func
|
||||
| TODO_ggc_collect
|
||||
| TODO_update_ssa
|
||||
| TODO_verify_ssa, /* todo_flags_finish */
|
||||
0 /* letter */
|
||||
};
|
||||
|
|
|
|||
Loading…
Reference in New Issue