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To: gcc-patches@gcc.gnu.org Subject: PR 71020: Handle abnormal PHIs in tree-call-cdce.c From: Richard Sandiford <richard.sandiford@arm.com> Gcc: private.sent --text follows this line-- The PR is about a case where tree-call-cdce.c causes two abnormal PHIs for the same variable to be live at the same time, leading to a coalescing failure. It seemed like getting rid of these kinds of input would be generally useful, so I added a utility to tree-dfa.c. Tested on x86_64-linux-gnu. gcc/ PR middle-end/71020 * tree-dfa.h (replace_abnormal_ssa_names): Declare. * tree-dfa.c (replace_abnormal_ssa_names): New function. * tree-call-cdce.c: Include tree-dfa.h. (can_guard_call_p): New function, extracted from... (can_use_internal_fn): ...here. (shrink_wrap_one_built_in_call_with_conds): Remove failure path and return void. (shrink_wrap_one_built_in_call): Likewise. (use_internal_fn): Likewise. (shrink_wrap_conditional_dead_built_in_calls): Update accordingly and return void. Call replace_abnormal_ssa_names. (pass_call_cdce::execute): Check can_guard_call_p during the initial walk. Assume shrink_wrap_conditional_dead_built_in_calls will always change something. gcc/testsuite/ * gcc.dg/torture/pr71020.c: New test. From-SVN: r236393
This commit is contained in:
Richard Sandiford
Richard Sandiford
parent
29799e9db1
commit
cf8be00de9
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@ -1,3 +1,21 @@
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2016-05-18 Richard Sandiford <richard.sandiford@arm.com>
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PR middle-end/71020
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* tree-dfa.h (replace_abnormal_ssa_names): Declare.
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* tree-dfa.c (replace_abnormal_ssa_names): New function.
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* tree-call-cdce.c: Include tree-dfa.h.
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(can_guard_call_p): New function, extracted from...
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(can_use_internal_fn): ...here.
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(shrink_wrap_one_built_in_call_with_conds): Remove failure path
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and return void.
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(shrink_wrap_one_built_in_call): Likewise.
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(use_internal_fn): Likewise.
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(shrink_wrap_conditional_dead_built_in_calls): Update accordingly
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and return void. Call replace_abnormal_ssa_names.
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(pass_call_cdce::execute): Check can_guard_call_p during the
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initial walk. Assume shrink_wrap_conditional_dead_built_in_calls
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will always change something.
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2016-05-18 Martin Jambor <mjambor@suse.cz>
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PR ipa/70646
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@ -1,3 +1,7 @@
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2016-05-18 Richard Sandiford <richard.sandiford@arm.com>
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* gcc.dg/torture/pr71020.c: New test.
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2016-05-18 Martin Jambor <mjambor@suse.cz>
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PR ipa/70646
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@ -0,0 +1,76 @@
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/* { dg-options "-funsafe-math-optimizations" } */
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double random_double (void);
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int setjmp (void *);
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void do_something (void);
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#define TEST_UNARY(FUNC) \
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double \
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FUNC##_dead (void *buffer) \
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{ \
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double d = random_double (); \
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setjmp (buffer); \
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__builtin_##FUNC (d); \
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d += 1; \
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do_something (); \
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return d; \
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} \
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\
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double \
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FUNC##_live (void *buffer) \
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{ \
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double d = random_double (); \
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setjmp (buffer); \
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d = __builtin_##FUNC (d); \
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do_something (); \
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return d; \
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}
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#define TEST_BINARY(FUNC) \
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double \
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FUNC##_dead (void *buffer) \
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{ \
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double d1 = random_double (); \
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double d2 = random_double (); \
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setjmp (buffer); \
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__builtin_##FUNC (d1, d2); \
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d1 += 1; \
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d2 += 1; \
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do_something (); \
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return d1 + d2; \
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} \
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\
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double \
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FUNC##_live (void *buffer) \
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{ \
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double d1 = random_double (); \
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double d2 = random_double (); \
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setjmp (buffer); \
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d1 = __builtin_##FUNC (d1, d2); \
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d2 += 1; \
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return d1 + d2; \
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}
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TEST_UNARY (acos)
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TEST_UNARY (asin)
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TEST_UNARY (asinh)
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TEST_UNARY (atan)
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TEST_UNARY (atanh)
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TEST_UNARY (cos)
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TEST_UNARY (cosh)
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TEST_UNARY (exp)
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TEST_UNARY (expm1)
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TEST_UNARY (exp2)
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TEST_UNARY (exp10)
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TEST_UNARY (log)
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TEST_UNARY (log2)
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TEST_UNARY (log10)
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TEST_UNARY (log1p)
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TEST_UNARY (significand)
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TEST_UNARY (sin)
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TEST_UNARY (sinh)
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TEST_UNARY (sqrt)
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TEST_BINARY (fmod)
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TEST_BINARY (remainder)
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@ -35,6 +35,7 @@ along with GCC; see the file COPYING3. If not see
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#include "tree-into-ssa.h"
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#include "builtins.h"
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#include "internal-fn.h"
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#include "tree-dfa.h"
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/* This pass serves two closely-related purposes:
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@ -349,6 +350,15 @@ edom_only_function (gcall *call)
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return false;
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}
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}
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/* Return true if it is structurally possible to guard CALL. */
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static bool
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can_guard_call_p (gimple *call)
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{
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return (!stmt_ends_bb_p (call)
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|| find_fallthru_edge (gimple_bb (call)->succs));
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}
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/* A helper function to generate gimple statements for one bound
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comparison, so that the built-in function is called whenever
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@ -747,11 +757,9 @@ gen_shrink_wrap_conditions (gcall *bi_call, vec<gimple *> conds,
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#define ERR_PROB 0.01
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/* Shrink-wrap BI_CALL so that it is only called when one of the NCONDS
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conditions in CONDS is false.
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conditions in CONDS is false. */
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Return true on success, in which case the cfg will have been updated. */
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static bool
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static void
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shrink_wrap_one_built_in_call_with_conds (gcall *bi_call, vec <gimple *> conds,
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unsigned int nconds)
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{
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@ -795,11 +803,10 @@ shrink_wrap_one_built_in_call_with_conds (gcall *bi_call, vec <gimple *> conds,
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/* Now find the join target bb -- split bi_call_bb if needed. */
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if (stmt_ends_bb_p (bi_call))
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{
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/* If the call must be the last in the bb, don't split the block,
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it could e.g. have EH edges. */
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/* We checked that there was a fallthrough edge in
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can_guard_call_p. */
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join_tgt_in_edge_from_call = find_fallthru_edge (bi_call_bb->succs);
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if (join_tgt_in_edge_from_call == NULL)
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return false;
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gcc_assert (join_tgt_in_edge_from_call);
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free_dominance_info (CDI_DOMINATORS);
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}
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else
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@ -898,28 +905,19 @@ shrink_wrap_one_built_in_call_with_conds (gcall *bi_call, vec <gimple *> conds,
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" into error conditions.\n",
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LOCATION_FILE (loc), LOCATION_LINE (loc));
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}
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return true;
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}
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/* Shrink-wrap BI_CALL so that it is only called when it might set errno
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(but is always called if it would set errno).
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(but is always called if it would set errno). */
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Return true on success, in which case the cfg will have been updated. */
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static bool
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static void
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shrink_wrap_one_built_in_call (gcall *bi_call)
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{
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unsigned nconds = 0;
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auto_vec<gimple *, 12> conds;
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gen_shrink_wrap_conditions (bi_call, conds, &nconds);
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/* This can happen if the condition generator decides
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it is not beneficial to do the transformation. Just
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return false and do not do any transformation for
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the call. */
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if (nconds == 0)
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return false;
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return shrink_wrap_one_built_in_call_with_conds (bi_call, conds, nconds);
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gcc_assert (nconds != 0);
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shrink_wrap_one_built_in_call_with_conds (bi_call, conds, nconds);
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}
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/* Return true if built-in function call CALL could be implemented using
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@ -933,11 +931,6 @@ can_use_internal_fn (gcall *call)
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if (!gimple_vdef (call))
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return false;
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/* Punt if we can't conditionalize the call. */
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basic_block bb = gimple_bb (call);
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if (stmt_ends_bb_p (call) && !find_fallthru_edge (bb->succs))
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return false;
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/* See whether there is an internal function for this built-in. */
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if (replacement_internal_fn (call) == IFN_LAST)
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return false;
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@ -951,18 +944,25 @@ can_use_internal_fn (gcall *call)
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return true;
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}
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/* Implement built-in function call CALL using an internal function.
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Return true on success, in which case the cfg will have changed. */
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/* Implement built-in function call CALL using an internal function. */
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static bool
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static void
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use_internal_fn (gcall *call)
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{
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/* We'll be inserting another call with the same arguments after the
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lhs has been set, so prevent any possible coalescing failure from
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having both values live at once. See PR 71020. */
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replace_abnormal_ssa_names (call);
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unsigned nconds = 0;
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auto_vec<gimple *, 12> conds;
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if (can_test_argument_range (call))
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gen_shrink_wrap_conditions (call, conds, &nconds);
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if (nconds == 0 && !edom_only_function (call))
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return false;
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{
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gen_shrink_wrap_conditions (call, conds, &nconds);
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gcc_assert (nconds != 0);
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}
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else
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gcc_assert (edom_only_function (call));
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internal_fn ifn = replacement_internal_fn (call);
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gcc_assert (ifn != IFN_LAST);
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@ -1008,35 +1008,26 @@ use_internal_fn (gcall *call)
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}
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}
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if (!shrink_wrap_one_built_in_call_with_conds (call, conds, nconds))
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/* It's too late to back out now. */
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gcc_unreachable ();
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return true;
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shrink_wrap_one_built_in_call_with_conds (call, conds, nconds);
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}
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/* The top level function for conditional dead code shrink
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wrapping transformation. */
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static bool
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static void
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shrink_wrap_conditional_dead_built_in_calls (vec<gcall *> calls)
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{
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bool changed = false;
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unsigned i = 0;
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unsigned n = calls.length ();
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if (n == 0)
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return false;
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for (; i < n ; i++)
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{
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gcall *bi_call = calls[i];
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if (gimple_call_lhs (bi_call))
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changed |= use_internal_fn (bi_call);
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use_internal_fn (bi_call);
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else
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changed |= shrink_wrap_one_built_in_call (bi_call);
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shrink_wrap_one_built_in_call (bi_call);
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}
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return changed;
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}
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namespace {
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@ -1079,7 +1070,6 @@ pass_call_cdce::execute (function *fun)
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{
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basic_block bb;
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gimple_stmt_iterator i;
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bool something_changed = false;
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auto_vec<gcall *> cond_dead_built_in_calls;
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FOR_EACH_BB_FN (bb, fun)
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{
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@ -1096,7 +1086,8 @@ pass_call_cdce::execute (function *fun)
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&& gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)
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&& (gimple_call_lhs (stmt)
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? can_use_internal_fn (stmt)
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: can_test_argument_range (stmt)))
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: can_test_argument_range (stmt))
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&& can_guard_call_p (stmt))
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{
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if (dump_file && (dump_flags & TDF_DETAILS))
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{
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@ -1114,19 +1105,12 @@ pass_call_cdce::execute (function *fun)
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if (!cond_dead_built_in_calls.exists ())
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return 0;
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something_changed
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= shrink_wrap_conditional_dead_built_in_calls (cond_dead_built_in_calls);
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if (something_changed)
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{
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free_dominance_info (CDI_POST_DOMINATORS);
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/* As we introduced new control-flow we need to insert PHI-nodes
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for the call-clobbers of the remaining call. */
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mark_virtual_operands_for_renaming (fun);
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return TODO_update_ssa;
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}
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return 0;
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shrink_wrap_conditional_dead_built_in_calls (cond_dead_built_in_calls);
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free_dominance_info (CDI_POST_DOMINATORS);
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/* As we introduced new control-flow we need to insert PHI-nodes
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for the call-clobbers of the remaining call. */
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mark_virtual_operands_for_renaming (fun);
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return TODO_update_ssa;
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}
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} // anon namespace
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@ -823,6 +823,29 @@ stmt_references_abnormal_ssa_name (gimple *stmt)
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return false;
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}
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/* If STMT takes any abnormal PHI values as input, replace them with
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local copies. */
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void
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replace_abnormal_ssa_names (gimple *stmt)
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{
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ssa_op_iter oi;
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use_operand_p use_p;
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FOR_EACH_SSA_USE_OPERAND (use_p, stmt, oi, SSA_OP_USE)
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{
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tree op = USE_FROM_PTR (use_p);
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if (TREE_CODE (op) == SSA_NAME && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
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{
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gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
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tree new_name = make_ssa_name (TREE_TYPE (op));
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gassign *assign = gimple_build_assign (new_name, op);
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gsi_insert_before (&gsi, assign, GSI_SAME_STMT);
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SET_USE (use_p, new_name);
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}
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}
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}
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/* Pair of tree and a sorting index, for dump_enumerated_decls. */
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struct GTY(()) numbered_tree
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{
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@ -35,6 +35,7 @@ extern tree get_addr_base_and_unit_offset_1 (tree, HOST_WIDE_INT *,
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tree (*) (tree));
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extern tree get_addr_base_and_unit_offset (tree, HOST_WIDE_INT *);
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extern bool stmt_references_abnormal_ssa_name (gimple *);
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extern void replace_abnormal_ssa_names (gimple *);
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extern void dump_enumerated_decls (FILE *, int);
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