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a80d668215
I noticed this in the code compiled for a routine using std::map, which produced this code: %25 = tail call i32 @memcmp(i8* %24, i8* %23, i32 6) nounwind readonly %.lobit.i = lshr i32 %25, 31 ; <i32> [#uses=1] %tmp.i = trunc i32 %.lobit.i to i8 ; <i8> [#uses=1] %toBool = icmp eq i8 %tmp.i, 0 ; <i1> [#uses=1] br i1 %toBool, label %bb3, label %bb4 which compiled to: call L_memcmp$stub shrl $31, %eax testb %al, %al jne LBB1_11 ## with this change, we compile it to: call L_memcmp$stub testl %eax, %eax js LBB1_11 This triggers all the time in common code, with patters like this: %169 = and i32 %ply, 1 ; <i32> [#uses=1] %170 = trunc i32 %169 to i8 ; <i8> [#uses=1] %toBool = icmp ne i8 %170, 0 ; <i1> [#uses=1] %7 = lshr i32 %6, 24 ; <i32> [#uses=1] %9 = trunc i32 %7 to i8 ; <i8> [#uses=1] %10 = icmp ne i8 %9, 0 ; <i1> [#uses=1] etc git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61985 91177308-0d34-0410-b5e6-96231b3b80d8
This directory contains test cases for the instcombine transformation. The dated tests are actual bug tests, whereas the named tests are used to test for features that the this pass should be capable of performing.