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Diffstat (limited to 'lib/Target/README.txt')
| -rw-r--r-- | lib/Target/README.txt | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/lib/Target/README.txt b/lib/Target/README.txt index fa5e6010cf..a02863c6a4 100644 --- a/lib/Target/README.txt +++ b/lib/Target/README.txt @@ -1964,4 +1964,41 @@ This occurs several times in viterbi. //===---------------------------------------------------------------------===// +This code (from Benchmarks/Dhrystone/dry.c): + +define i32 @Func1(i32, i32) nounwind readnone optsize ssp { +entry: + %sext = shl i32 %0, 24 + %conv = ashr i32 %sext, 24 + %sext6 = shl i32 %1, 24 + %conv4 = ashr i32 %sext6, 24 + %cmp = icmp eq i32 %conv, %conv4 + %. = select i1 %cmp, i32 10000, i32 0 + ret i32 %. +} + +Should be simplified into something like: + +define i32 @Func1(i32, i32) nounwind readnone optsize ssp { +entry: + %sext = shl i32 %0, 24 + %conv = and i32 %sext, 0xFF000000 + %sext6 = shl i32 %1, 24 + %conv4 = and i32 %sext6, 0xFF000000 + %cmp = icmp eq i32 %conv, %conv4 + %. = select i1 %cmp, i32 10000, i32 0 + ret i32 %. +} + +and then to: + +define i32 @Func1(i32, i32) nounwind readnone optsize ssp { +entry: + %conv = and i32 %0, 0xFF + %conv4 = and i32 %1, 0xFF + %cmp = icmp eq i32 %conv, %conv4 + %. = select i1 %cmp, i32 10000, i32 0 + ret i32 %. +} +//===---------------------------------------------------------------------===// |