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re PR middle-end/54149 (write introduction incorrect wrt the C11 memory model)

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PR middle-end/54149
        * tree-ssa-loop-im.c (execute_sm_if_changed_flag_set): Only set
        flag for writes.

From-SVN: r191179
This commit is contained in:
Aldy Hernandez 2012-09-11 12:28:02 +00:00 committed by Aldy Hernandez
parent ccdbfe9398
commit e0a6637cbd
3 changed files with 68 additions and 3 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2012-09-11 Aldy Hernandez <aldyh@redhat.com>
PR middle-end/54149
* tree-ssa-loop-im.c (execute_sm_if_changed_flag_set): Only set
flag for writes.
2012-09-11 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
PR tree-optimization/55492

54
gcc/testsuite/gcc.dg/simulate-thread/speculative-store-4.c Normal file
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@ -0,0 +1,54 @@
/* { dg-do link } */
/* { dg-options "--param allow-store-data-races=0" } */
/* { dg-final { simulate-thread } } */
#include <stdio.h>
#include <stdlib.h>
#include "simulate-thread.h"
/* PR 54139 */
/* Test that speculative stores do not happen for --param
allow-store-data-races=0. */
int g_13=1, insns=1;
__attribute__((noinline))
void simulate_thread_main()
{
int l_245;
/* Since g_13 is unilaterally set positive above, there should be
no store to g_13 below. */
for (l_245 = 0; l_245 <= 1; l_245 += 1)
for (; g_13 <= 0; g_13 = 1)
;
}
int main()
{
simulate_thread_main ();
simulate_thread_done ();
return 0;
}
void simulate_thread_other_threads ()
{
++g_13;
++insns;
}
int simulate_thread_step_verify ()
{
return 0;
}
int simulate_thread_final_verify ()
{
if (g_13 != insns)
{
printf("FAIL: g_13 was incorrectly cached\n");
return 1;
}
return 0;
}

11
gcc/tree-ssa-loop-im.c
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@ -2113,9 +2113,14 @@ execute_sm_if_changed_flag_set (struct loop *loop, mem_ref_p ref)
gimple_stmt_iterator gsi;
gimple stmt;
gsi = gsi_for_stmt (loc->stmt);
stmt = gimple_build_assign (flag, boolean_true_node);
gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING);
/* Only set the flag for writes. */
if (is_gimple_assign (loc->stmt)
&& gimple_assign_lhs_ptr (loc->stmt) == loc->ref)
{
gsi = gsi_for_stmt (loc->stmt);
stmt = gimple_build_assign (flag, boolean_true_node);
gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING);
}
}
VEC_free (mem_ref_loc_p, heap, locs);
return flag;