mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-24 11:42:57 +01:00
303a9b2e50
Original message: The attached is the fix to radar://11663049. The optimization can be outlined by following rules: (select (x != c), e, c) -> select (x != c), e, x), (select (x == c), c, e) -> select (x == c), x, e) where the <c> is an integer constant. The reason for this change is that : on x86, conditional-move-from-constant needs two instructions; however, conditional-move-from-register need only one instruction. While the LowerSELECT() sounds to be the most convenient place for this optimization, it turns out to be a bad place. The reason is that by replacing the constant <c> with a symbolic value, it obscure some instruction-combining opportunities which would otherwise be very easy to spot. For that reason, I have to postpone the change to last instruction-combining phase. The change passes the test of "make check-all -C <build-root/test" and "make -C project/test-suite/SingleSource". llvm-svn: 165661 |
||
---|---|---|
.. | ||
Analysis | ||
Archive | ||
AsmParser | ||
Bitcode | ||
CodeGen | ||
DebugInfo | ||
ExecutionEngine | ||
Linker | ||
MC | ||
Object | ||
Support | ||
TableGen | ||
Target | ||
Transforms | ||
VMCore | ||
CMakeLists.txt | ||
LLVMBuild.txt | ||
Makefile |