The following patch addresses the issue that asms which clobber
hard registers are no optimization barriers for local hardreg
vars on GIMPLE.
Bootstrapped / tested on x86_64-unknown-linux-gnu.
OK?
Thanks,
Richard.
2019-03-29 Richard Biener <rguent...@suse.de>
PR tree-optimization/87984
* gimple.c (gimple_asm_clobbers_memory_p): Treat asms
which clobber registers as modifying memory.
Index: gcc/gimple.c
===================================================================
--- gcc/gimple.c (revision 270012)
+++ gcc/gimple.c (working copy)
@@ -2727,11 +2738,16 @@ gimple_asm_clobbers_memory_p (const gasm
{
unsigned i;
+ /* While strictly speaking only a "memory" clobber denotes clobbering
+ memory in GIMPLE we also treat local hard-register variables as
+ memory so simply treat all clobbers as memory. The only exception
+ is the special clobber "cc". */
for (i = 0; i < gimple_asm_nclobbers (stmt); i++)
{
tree op = gimple_asm_clobber_op (stmt, i);
- if (strcmp (TREE_STRING_POINTER (TREE_VALUE (op)), "memory") == 0)
- return true;
+ if (strcmp (TREE_STRING_POINTER (TREE_VALUE (op)), "cc") == 0)
+ continue;
+ return true;
}
/* Non-empty basic ASM implicitly clobbers memory. */
