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dagcombine miscompilation of shifts #1845

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lattner opened this issue May 30, 2007 · 1 comment
Closed

dagcombine miscompilation of shifts #1845

lattner opened this issue May 30, 2007 · 1 comment
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bugzilla Issues migrated from bugzilla llvm:codegen miscompilation

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@lattner
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lattner commented May 30, 2007

Bugzilla Link 1473
Resolution FIXED
Resolved on Feb 22, 2010 12:54
Version trunk
OS All

Extended Description

dag combine is miscompiling this on ppc:
define i8 @​foo(i16 zext %a) zext {
entry:
%tmp2 = lshr i16 %a, 10 ; [#uses=1]
%tmp23 = trunc i16 %tmp2 to i8 ; [#uses=1]
%tmp4 = shl i8 %tmp23, 1 ; [#uses=1]
%tmp5 = and i8 %tmp4, 2 ; [#uses=1]
ret i8 %tmp5
}

-Chris
@lattner
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lattner commented May 30, 2007

Fixed. Patch here:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20070528/050089.html

Testcase here: CodeGen/PowerPC/2007-05-30-dagcombine-miscomp.ll

-Chris

@llvmbot llvmbot transferred this issue from llvm/llvm-bugzilla-archive Dec 3, 2021
troelsbjerre pushed a commit to troelsbjerre/llvm-project that referenced this issue Jan 10, 2024
@jimingham
Merge pull request llvm#1845 from jimingham/delete-disabled
e40e736 
Add `breakpoint delete --disabled`: deletes all disabled breakpoints.
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