[llvm-commits] [llvm] r143214 - in /llvm/trunk: lib/Analysis/InstructionSimplify.cpp test/Transforms/InstSimplify/compare.ll

Eli Friedman eli.friedman at gmail.com
Fri Oct 28 16:56:06 PDT 2011


On Fri, Oct 28, 2011 at 12:01 PM, Duncan Sands <baldrick at free.fr> wrote:
> Author: baldrick
> Date: Fri Oct 28 14:01:20 2011
> New Revision: 143214
>
> URL: http://llvm.org/viewvc/llvm-project?rev=143214&view=rev
> Log:
> The expression icmp eq (select (icmp eq x, 0), 1, x), 0 folds to false.
> Spotted by my super-optimizer in 186.crafty and 450.soplex.  We really
> need a proper infrastructure for handling generalizations of this kind
> of thing (which occur a lot), however this case is so simple that I decided
> to go ahead and implement it directly.

This appears to be causing a miscompile on
MultiSource/Benchmarks/mediabench/gsm/toast, among other things.

-Eli




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