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Diffstat (limited to 'gcc/tree-ssa-operands.c')
| -rw-r--r-- | gcc/tree-ssa-operands.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/gcc/tree-ssa-operands.c b/gcc/tree-ssa-operands.c index 0f27912..3b5de9b 100644 --- a/gcc/tree-ssa-operands.c +++ b/gcc/tree-ssa-operands.c @@ -1460,7 +1460,17 @@ get_call_expr_operands (tree stmt, tree expr) tree op; int call_flags = call_expr_flags (expr); - if (!bitmap_empty_p (call_clobbered_vars)) + /* If aliases have been computed already, add V_MAY_DEF or V_USE + operands for all the symbols that have been found to be + call-clobbered. + + Note that if aliases have not been computed, the global effects + of calls will not be included in the SSA web. This is fine + because no optimizer should run before aliases have been + computed. By not bothering with virtual operands for CALL_EXPRs + we avoid adding superfluous virtual operands, which can be a + significant compile time sink (See PR 15855). */ + if (aliases_computed_p && !bitmap_empty_p (call_clobbered_vars)) { /* A 'pure' or a 'const' functions never call clobber anything. A 'noreturn' function might, but since we don't return anyway |