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| -rw-r--r-- | llvm/test/Transforms/CodeGenPrepare/X86/cttz-ctlz.ll | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/cttz-ctlz.ll b/llvm/test/Transforms/CodeGenPrepare/X86/cttz-ctlz.ll new file mode 100644 index 00000000000..72d82e2a162 --- /dev/null +++ b/llvm/test/Transforms/CodeGenPrepare/X86/cttz-ctlz.ll @@ -0,0 +1,56 @@ +; RUN: opt -S -codegenprepare < %s | FileCheck %s --check-prefix=SLOW +; RUN: opt -S -codegenprepare -mattr=+bmi < %s | FileCheck %s --check-prefix=FAST_TZ +; RUN: opt -S -codegenprepare -mattr=+lzcnt < %s | FileCheck %s --check-prefix=FAST_LZ + +target triple = "x86_64-unknown-unknown" +target datalayout = "e-n32:64" + +; If the intrinsic is cheap, nothing should change. +; If the intrinsic is expensive, check if the input is zero to avoid the call. +; This is undoing speculation that may have been created by SimplifyCFG + InstCombine. + +define i64 @cttz(i64 %A) { +entry: + %z = call i64 @llvm.cttz.i64(i64 %A, i1 false) + ret i64 %z + +; SLOW-LABEL: @cttz( +; SLOW: entry: +; SLOW: %cmpz = icmp eq i64 %A, 0 +; SLOW: br i1 %cmpz, label %cond.end, label %cond.false +; SLOW: cond.false: +; SLOW: %z = call i64 @llvm.cttz.i64(i64 %A, i1 true) +; SLOW: br label %cond.end +; SLOW: cond.end: +; SLOW: %ctz = phi i64 [ 64, %entry ], [ %z, %cond.false ] +; SLOW: ret i64 %ctz + +; FAST_TZ-LABEL: @cttz( +; FAST_TZ: %z = call i64 @llvm.cttz.i64(i64 %A, i1 false) +; FAST_TZ: ret i64 %z +} + +define i64 @ctlz(i64 %A) { +entry: + %z = call i64 @llvm.ctlz.i64(i64 %A, i1 false) + ret i64 %z + +; SLOW-LABEL: @ctlz( +; SLOW: entry: +; SLOW: %cmpz = icmp eq i64 %A, 0 +; SLOW: br i1 %cmpz, label %cond.end, label %cond.false +; SLOW: cond.false: +; SLOW: %z = call i64 @llvm.ctlz.i64(i64 %A, i1 true) +; SLOW: br label %cond.end +; SLOW: cond.end: +; SLOW: %ctz = phi i64 [ 64, %entry ], [ %z, %cond.false ] +; SLOW: ret i64 %ctz + +; FAST_LZ-LABEL: @ctlz( +; FAST_LZ: %z = call i64 @llvm.ctlz.i64(i64 %A, i1 false) +; FAST_LZ: ret i64 %z +} + +declare i64 @llvm.cttz.i64(i64, i1) +declare i64 @llvm.ctlz.i64(i64, i1) + |
