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| author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-03-29 17:22:39 +0000 |
|---|---|---|
| committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-03-29 17:22:39 +0000 |
| commit | 4e55044ff52029c2345639008aab5c7a1f21cfb8 (patch) | |
| tree | 567db4cf1beb44cc08bc83c844faa00fba1fe78f /clang/lib/CodeGen/CGBlocks.h | |
| parent | 3e2320c8bee630fe1ffb551dc04f2ad27636d912 (diff) | |
| download | bcm5719-llvm-4e55044ff52029c2345639008aab5c7a1f21cfb8.tar.gz bcm5719-llvm-4e55044ff52029c2345639008aab5c7a1f21cfb8.zip | |
Don't PRE compares.
CodeGenPrepare sinks compare instructions down to their uses to prevent
live flags and predicate registers across basic blocks.
PRE of a compare instruction prevents that, forcing the i1 compare
result into a general purpose register. That is usually more expensive
than the redundant compare PRE was trying to eliminate in the first
place.
llvm-svn: 153657
Diffstat (limited to 'clang/lib/CodeGen/CGBlocks.h')
0 files changed, 0 insertions, 0 deletions
