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| author | Richard Biener <rguenther@suse.de> | 2021-10-07 14:24:03 +0200 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2021-10-07 14:28:00 +0200 |
| commit | 1ebf2c14c60f5f37c00bea66aba46c25d4bcf473 (patch) | |
| tree | 43929737d78740d78c40566d03b5f3a18b0666ac /gcc/tree-ssa-sccvn.c | |
| parent | 4fcf7f6800ffde9fd5ebc06e03937f55f80f68ec (diff) | |
| download | gcc-1ebf2c14c60f5f37c00bea66aba46c25d4bcf473.zip gcc-1ebf2c14c60f5f37c00bea66aba46c25d4bcf473.tar.gz gcc-1ebf2c14c60f5f37c00bea66aba46c25d4bcf473.tar.bz2 | |
tree-optimization/102608 - avoid CSEing .DEFERRED_INIT
This makes VN not CSE .DEFERRED_INIT which confuses uninit
analysis which reports the wrong decl when facing copies
of not initialized data.
2021-10-07 Richard Biener <rguenther@suse.de>
PR tree-optimization/102608
* tree-ssa-sccvn.c (visit_stmt): Drop .DEFERRED_INIT to
varying.
Diffstat (limited to 'gcc/tree-ssa-sccvn.c')
| -rw-r--r-- | gcc/tree-ssa-sccvn.c | 45 |
1 files changed, 24 insertions, 21 deletions
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index 0d94221..ae0172a 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -5668,27 +5668,30 @@ visit_stmt (gimple *stmt, bool backedges_varying_p = false) && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL) extra_fnflags = flags_from_decl_or_type (TREE_OPERAND (fn, 0)); } - if (/* Calls to the same function with the same vuse - and the same operands do not necessarily return the same - value, unless they're pure or const. */ - ((gimple_call_flags (call_stmt) | extra_fnflags) - & (ECF_PURE | ECF_CONST)) - /* If calls have a vdef, subsequent calls won't have - the same incoming vuse. So, if 2 calls with vdef have the - same vuse, we know they're not subsequent. - We can value number 2 calls to the same function with the - same vuse and the same operands which are not subsequent - the same, because there is no code in the program that can - compare the 2 values... */ - || (gimple_vdef (call_stmt) - /* ... unless the call returns a pointer which does - not alias with anything else. In which case the - information that the values are distinct are encoded - in the IL. */ - && !(gimple_call_return_flags (call_stmt) & ERF_NOALIAS) - /* Only perform the following when being called from PRE - which embeds tail merging. */ - && default_vn_walk_kind == VN_WALK)) + if ((/* Calls to the same function with the same vuse + and the same operands do not necessarily return the same + value, unless they're pure or const. */ + ((gimple_call_flags (call_stmt) | extra_fnflags) + & (ECF_PURE | ECF_CONST)) + /* If calls have a vdef, subsequent calls won't have + the same incoming vuse. So, if 2 calls with vdef have the + same vuse, we know they're not subsequent. + We can value number 2 calls to the same function with the + same vuse and the same operands which are not subsequent + the same, because there is no code in the program that can + compare the 2 values... */ + || (gimple_vdef (call_stmt) + /* ... unless the call returns a pointer which does + not alias with anything else. In which case the + information that the values are distinct are encoded + in the IL. */ + && !(gimple_call_return_flags (call_stmt) & ERF_NOALIAS) + /* Only perform the following when being called from PRE + which embeds tail merging. */ + && default_vn_walk_kind == VN_WALK)) + /* Do not process .DEFERRED_INIT since that confuses uninit + analysis. */ + && !gimple_call_internal_p (call_stmt, IFN_DEFERRED_INIT)) changed = visit_reference_op_call (lhs, call_stmt); else changed = defs_to_varying (call_stmt); |