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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2011-01-17 12:04:57 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2011-01-17 12:04:57 +0000 |
| commit | d8228924556d3c465da5b858c620b29fd1cf298e (patch) | |
| tree | 76f23c5534b12780db45975b1f85f6f077fc77b6 /test/CodeGen/X86/ctpop-combine.ll | |
| parent | 8702e8be8df5f2ba12ecc89580d5e7453a1a39cd (diff) | |
| download | llvm-d8228924556d3c465da5b858c620b29fd1cf298e.tar.gz llvm-d8228924556d3c465da5b858c620b29fd1cf298e.tar.bz2 llvm-d8228924556d3c465da5b858c620b29fd1cf298e.tar.xz | |
Add a DAGCombine to turn (ctpop x) u< 2 into (x & x-1) == 0.
This shaves off 4 popcounts from the hacked 186.crafty source.
This is enabled even when a native popcount instruction is available. The
combined code is one operation longer but it should be faster nevertheless.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123621 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/CodeGen/X86/ctpop-combine.ll')
| -rw-r--r-- | test/CodeGen/X86/ctpop-combine.ll | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/test/CodeGen/X86/ctpop-combine.ll b/test/CodeGen/X86/ctpop-combine.ll new file mode 100644 index 0000000000..b87637f942 --- /dev/null +++ b/test/CodeGen/X86/ctpop-combine.ll @@ -0,0 +1,31 @@ +; RUN: llc -march=x86-64 < %s | FileCheck %s + +declare i64 @llvm.ctpop.i64(i64) nounwind readnone + +define i32 @test1(i64 %x) nounwind readnone { + %count = tail call i64 @llvm.ctpop.i64(i64 %x) + %cast = trunc i64 %count to i32 + %cmp = icmp ugt i32 %cast, 1 + %conv = zext i1 %cmp to i32 + ret i32 %conv +; CHECK: test1: +; CHECK: leaq -1(%rdi) +; CHECK-NEXT: testq +; CHECK-NEXT: setne +; CHECK: ret +} + + +define i32 @test2(i64 %x) nounwind readnone { + %count = tail call i64 @llvm.ctpop.i64(i64 %x) + %cast = trunc i64 %count to i32 + %cmp = icmp ult i32 %cast, 2 + %conv = zext i1 %cmp to i32 + ret i32 %conv +; CHECK: test2: +; CHECK: leaq -1(%rdi) +; CHECK-NEXT: testq +; CHECK-NEXT: sete +; CHECK: ret +} + |