re PR middle-end/61912 (Missed (partial) dead store elimination for structures on GIMPLE)
PR tree-optimization/61912 PR tree-optimization/77485 * tree-ssa-dse.c: Include expr.h. (maybe_trim_constructor_store): New function. (maybe_trim_partially_dead_store): Call maybe_trim_constructor_store. PR tree-optimization/61912 PR tree-optimization/77485 * g++.dg/tree-ssa/ssa-dse-1.C: New test. * gcc.dg/tree-ssa/pr30375: Adjust expected output. * gcc.dg/tree-ssa/ssa-dse-24.c: New test. From-SVN: r244443
This commit is contained in:
Jeff Law
Jeff Law
parent
d155c6fef0
commit
9e59e99a60
@ -1,8 +1,14 @@
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2017-01-13 Jeff Law <law@redhat.com>
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PR tree-optimization/33562
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PR tree-optimization/61912
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PR tree-optimization/77485
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PR tree-optimization/61912
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PR tree-optimization/77485
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* tree-ssa-dse.c: Include expr.h.
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(maybe_trim_constructor_store): New function.
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(maybe_trim_partially_dead_store): Call maybe_trim_constructor_store.
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PR tree-optimization/33562
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PR tree-optimization/61912
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PR tree-optimization/77485
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* doc/invoke.texi: Document new dse-max-object-size param.
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* params.def (PARM_DSE_MAX_OBJECT_SIZE): New PARAM.
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* tree-ssa-dse.c: Include params.h.
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@ -1,8 +1,14 @@
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2017-01-13 Jeff Law <law@redhat.com>
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PR tree-optimization/33562
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PR tree-optimization/61912
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PR tree-optimization/77485
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PR tree-optimization/61912
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PR tree-optimization/77485
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* g++.dg/tree-ssa/ssa-dse-1.C: New test.
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* gcc.dg/tree-ssa/pr30375: Adjust expected output.
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* gcc.dg/tree-ssa/ssa-dse-24.c: New test.
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PR tree-optimization/33562
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PR tree-optimization/61912
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PR tree-optimization/77485
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* gcc.dg/tree-ssa/complex-4.c: Remove xfail.
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* gcc.dg/tree-ssa/complex-5.c: Likewise.
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* gcc.dg/tree-ssa/ssa-dse-9.c: Likewise.
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101
gcc/testsuite/g++.dg/tree-ssa/ssa-dse-1.C
Normal file
101
gcc/testsuite/g++.dg/tree-ssa/ssa-dse-1.C
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@ -0,0 +1,101 @@
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/* { dg-do compile } */
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/* { dg-options "-std=c++14 -O -fdump-tree-dse1-details" } */
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using uint = unsigned int;
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template<typename C, uint S>
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struct FixBuf
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{
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C buf[S] = {};
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};
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template<typename C>
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struct OutBuf
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{
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C* cur;
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C* end;
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C* beg;
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template<uint S>
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constexpr
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OutBuf(FixBuf<C, S>& b) : cur{b.buf}, end{b.buf + S}, beg{b.buf} { }
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OutBuf(C* b, C* e) : cur{b}, end{e} { }
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OutBuf(C* b, uint s) : cur{b}, end{b + s} { }
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constexpr
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OutBuf& operator<<(C v)
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{
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if (cur < end) {
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*cur = v;
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}
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++cur;
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return *this;
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}
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constexpr
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OutBuf& operator<<(uint v)
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{
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uint q = v / 10U;
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uint r = v % 10U;
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if (q) {
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*this << q;
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}
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*this << static_cast<C>(r + '0');
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return *this;
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}
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};
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template<bool BOS>
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struct BufOrSize
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{
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template<typename C, uint S>
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static constexpr auto Select(FixBuf<C, S>& fb, OutBuf<C>&)
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{
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return fb;
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}
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};
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template<>
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struct BufOrSize<true>
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{
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template<typename C, uint S>
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static constexpr auto Select(FixBuf<C, S>&, OutBuf<C>& ob)
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{
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return ob.cur - ob.beg;
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}
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};
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// if BOS=1, it will return the size of the generated data, else the data itself
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template<uint N, uint S, bool BOS = 0>
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constexpr
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auto fixbuf()
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{
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FixBuf<char, S> fb;
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OutBuf<char> ob{fb};
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for (uint i = 0; i <= N; ++i) {
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ob << i << static_cast<char>(i == N ? 0 : ' ');
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}
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return BufOrSize<BOS>::Select(fb, ob);
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}
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auto foo()
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{
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constexpr auto x = fixbuf<13, 200>();
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return x;
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}
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auto foo_sized()
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{
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constexpr auto s = fixbuf<13, 0, 1>();
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constexpr auto x = fixbuf<13, s>();
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return x;
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}
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int main()
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{
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}
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/* { dg-final { scan-tree-dump-times "MEM\\\[\\(struct FixBuf \\*\\)&<retval> \\+ \[0-9\]+B\\\] = {}" 1 "dse1" } } */
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@ -22,4 +22,5 @@ void test_signed_msg_encoding(void)
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f();
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}
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/* { dg-final { scan-tree-dump-times "signInfo = {}" 1 "dse1" } } */
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/* { dg-final { scan-tree-dump-times "MEM\\\[\\(struct _s \\*\\)&signInfo \\+ \[0-9\]+B\\\] = {}" 1 "dse1" } } */
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62
gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-24.c
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62
gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-24.c
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@ -0,0 +1,62 @@
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/* { dg-do compile } */
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/* { dg-options "-O2 -fdump-tree-dse1" } */
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typedef unsigned int wchar_t;
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struct printf_info
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{
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int prec;
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int width;
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wchar_t spec;
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unsigned int is_long_double:1;
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unsigned int is_short:1;
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unsigned int is_long:1;
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unsigned int alt:1;
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unsigned int space:1;
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unsigned int left:1;
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unsigned int showsign:1;
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unsigned int group:1;
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unsigned int extra:1;
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unsigned int is_char:1;
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unsigned int wide:1;
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unsigned int i18n:1;
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unsigned int __pad:4;
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unsigned short int user;
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wchar_t pad;
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} info;
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void bar (struct printf_info *);
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void foo(int prec,
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int width,
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wchar_t spec,
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unsigned int is_long_double,
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unsigned int is_short,
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unsigned int is_long,
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unsigned int alt,
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unsigned int space,
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unsigned int left,
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unsigned int showsign,
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unsigned int group,
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wchar_t pad)
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{
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struct printf_info info = {
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.prec = prec,
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.width = width,
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.spec = spec,
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.is_long_double = is_long_double,
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.is_short = is_short,
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.is_long = is_long,
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.alt = alt,
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.space = space,
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.left = left,
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.showsign = showsign,
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.group = group,
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.pad = pad,
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.extra = 0,
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.wide = sizeof (char) != 1 };
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bar (&info);
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}
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/* { dg-final { scan-tree-dump-times "MEM\\\[\\(struct printf_info \\*\\)&info \\+ \[0-9\]+B\\\] = {}" 1 "dse1" } } */
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@ -34,6 +34,7 @@ along with GCC; see the file COPYING3. If not see
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#include "domwalk.h"
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#include "tree-cfgcleanup.h"
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#include "params.h"
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#include "alias.h"
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/* This file implements dead store elimination.
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@ -271,6 +272,66 @@ maybe_trim_complex_store (ao_ref *ref, sbitmap live, gimple *stmt)
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are live. We do not try to optimize those cases. */
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}
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/* STMT initializes an object using a CONSTRUCTOR where one or more of the
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bytes written are dead stores. ORIG is the bitmap of bytes stored by
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STMT. LIVE is the bitmap of stores that are actually live.
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Attempt to rewrite STMT so that only the real or imaginary part of
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the object is actually stored.
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The most common case for getting here is a CONSTRUCTOR with no elements
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being used to zero initialize an object. We do not try to handle other
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cases as those would force us to fully cover the object with the
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CONSTRUCTOR node except for the components that are dead. */
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static void
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maybe_trim_constructor_store (ao_ref *ref, sbitmap live, gimple *stmt)
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{
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tree ctor = gimple_assign_rhs1 (stmt);
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/* This is the only case we currently handle. It actually seems to
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catch most cases of actual interest. */
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gcc_assert (CONSTRUCTOR_NELTS (ctor) == 0);
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int head_trim = 0;
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int tail_trim = 0;
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compute_trims (ref, live, &head_trim, &tail_trim);
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/* Now we want to replace the constructor initializer
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with memset (object + head_trim, 0, size - head_trim - tail_trim). */
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if (head_trim || tail_trim)
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{
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/* We want &lhs for the MEM_REF expression. */
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tree lhs_addr = build_fold_addr_expr (gimple_assign_lhs (stmt));
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if (! is_gimple_min_invariant (lhs_addr))
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return;
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/* The number of bytes for the new constructor. */
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int count = (ref->size / BITS_PER_UNIT) - head_trim - tail_trim;
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/* And the new type for the CONSTRUCTOR. Essentially it's just
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a char array large enough to cover the non-trimmed parts of
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the original CONSTRUCTOR. Note we want explicit bounds here
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so that we know how many bytes to clear when expanding the
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CONSTRUCTOR. */
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tree type = build_array_type_nelts (char_type_node, count);
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/* Build a suitable alias type rather than using alias set zero
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to avoid pessimizing. */
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tree alias_type = reference_alias_ptr_type (gimple_assign_lhs (stmt));
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/* Build a MEM_REF representing the whole accessed area, starting
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at the first byte not trimmed. */
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tree exp = fold_build2 (MEM_REF, type, lhs_addr,
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build_int_cst (alias_type, head_trim));
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/* Now update STMT with a new RHS and LHS. */
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gimple_assign_set_lhs (stmt, exp);
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gimple_assign_set_rhs1 (stmt, build_constructor (type, NULL));
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}
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}
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/* STMT is a memory write where one or more bytes written are dead
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stores. ORIG is the bitmap of bytes stored by STMT. LIVE is the
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bitmap of stores that are actually live.
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@ -287,6 +348,9 @@ maybe_trim_partially_dead_store (ao_ref *ref, sbitmap live, gimple *stmt)
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{
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switch (gimple_assign_rhs_code (stmt))
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{
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case CONSTRUCTOR:
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maybe_trim_constructor_store (ref, live, stmt);
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break;
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case COMPLEX_CST:
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maybe_trim_complex_store (ref, live, stmt);
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break;
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