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| author | David Majnemer <david.majnemer@gmail.com> | 2013-06-29 10:28:04 +0000 |
|---|---|---|
| committer | David Majnemer <david.majnemer@gmail.com> | 2013-06-29 10:28:04 +0000 |
| commit | 5953d3712abd7b3fdb0f8442cd594350a1209204 (patch) | |
| tree | 8ef70c85ea4a08ee05bacea688c6a62d4146ba2b /llvm/lib/Target/Target.cpp | |
| parent | 92a8a7d45abc8207ee9a9c5282da7dc151aff3c7 (diff) | |
| download | bcm5719-llvm-5953d3712abd7b3fdb0f8442cd594350a1209204.tar.gz bcm5719-llvm-5953d3712abd7b3fdb0f8442cd594350a1209204.zip | |
InstCombine: FoldGEPICmp shouldn't change sign of base pointer comparison
Changing the sign when comparing the base pointer would introduce all
sorts of unexpected things like:
%gep.i = getelementptr inbounds [1 x i8]* %a, i32 0, i32 0
%gep2.i = getelementptr inbounds [1 x i8]* %b, i32 0, i32 0
%cmp.i = icmp ult i8* %gep.i, %gep2.i
%cmp.i1 = icmp ult [1 x i8]* %a, %b
%cmp = icmp ne i1 %cmp.i, %cmp.i1
ret i1 %cmp
into:
%cmp.i = icmp slt [1 x i8]* %a, %b
%cmp.i1 = icmp ult [1 x i8]* %a, %b
%cmp = xor i1 %cmp.i, %cmp.i1
ret i1 %cmp
By preserving the original sign, we now get:
ret i1 false
This fixes PR16483.
llvm-svn: 185259
Diffstat (limited to 'llvm/lib/Target/Target.cpp')
0 files changed, 0 insertions, 0 deletions
