Chris Lattner a80d668215 Implement rdar://6480391, extending of equality icmp's to avoid a truncation. ... 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		2009-01-09 07:47:06 +00:00
..
Hello	Initial support for the CMake build system.	2008-09-22 01:08:49 +00:00
Instrumentation	Use Function::getEntryBlock() instead of Function::front(), for clarity.	2008-10-21 03:10:28 +00:00
IPO	Adjustments to last patch based on review.	2009-01-09 01:30:11 +00:00
Scalar	Implement rdar://6480391, extending of equality icmp's to avoid a truncation.	2009-01-09 07:47:06 +00:00
Utils	Adjustments to last patch based on review.	2009-01-09 01:30:11 +00:00
Makefile	remove attribution from lib Makefiles.	2007-12-29 20:09:26 +00:00