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| author | Richard Biener <rguenther@suse.de> | 2020-06-04 13:44:58 +0200 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2020-06-05 08:35:44 +0200 |
| commit | 80d6f89e78fc3b772701988cc73aa8e8006283be (patch) | |
| tree | fe41e78187e7dc97dbb204546c0e8572c1f944ca /gcc/expr.c | |
| parent | 6c6931a353a6c41b2c9eb4bd2abec540104e940f (diff) | |
| download | gcc-80d6f89e78fc3b772701988cc73aa8e8006283be.zip gcc-80d6f89e78fc3b772701988cc73aa8e8006283be.tar.gz gcc-80d6f89e78fc3b772701988cc73aa8e8006283be.tar.bz2 | |
middle-end/95493 - bogus MEM_ATTRS for variable array access
The following patch avoids keeping the inherited MEM_ATTRS when
set_mem_attributes_minus_bitpos is called with a variable ARRAY_REF.
The inherited ones may not reflect the correct offset and neither
does the updated alias-set match the inherited MEM_EXPR. This all
ends up confusing path-based alias-analysis, causing wrong-code.
The fix is to stop not adopting a MEM_EXPR for certain kinds of
expressions and instead handle everything we can. There's still
the constant kind trees case which I'm too lazy to look into right
now. I did refrain from adding SSA_NAME there and instead avoided
calling set_mem_attributes_minus_bitpos when debug expression
expansion ended up expanding a SSA definition RHS which should
already have taken care of setting the appropriate MEM_ATTRS.
2020-06-04 Richard Biener <rguenther@suse.de>
PR middle-end/95493
* cfgexpand.c (expand_debug_expr): Avoid calling
set_mem_attributes_minus_bitpos when we were expanding
an SSA name.
* emit-rtl.c (set_mem_attributes_minus_bitpos): Remove
ARRAY_REF special-casing, add CONSTRUCTOR to the set of
special-cases we do not want MEM_EXPRs for. Assert
we end up with reasonable MEM_EXPRs.
* g++.dg/torture/pr95493.C: New testcase.
Diffstat (limited to 'gcc/expr.c')
0 files changed, 0 insertions, 0 deletions