diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Target/AArch64/AArch64ISelLowering.h | 8 | ||||
| -rw-r--r-- | llvm/test/Transforms/SimplifyCFG/AArch64/cttz-ctlz.ll | 43 |
2 files changed, 51 insertions, 0 deletions
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.h b/llvm/lib/Target/AArch64/AArch64ISelLowering.h index 091983387d9..c8d9ca3ef07 100644 --- a/llvm/lib/Target/AArch64/AArch64ISelLowering.h +++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.h @@ -381,6 +381,14 @@ public: return AArch64::X1; } + bool isCheapToSpeculateCttz() const override { + return true; + } + + bool isCheapToSpeculateCtlz() const override { + return true; + } + private: bool isExtFreeImpl(const Instruction *Ext) const override; diff --git a/llvm/test/Transforms/SimplifyCFG/AArch64/cttz-ctlz.ll b/llvm/test/Transforms/SimplifyCFG/AArch64/cttz-ctlz.ll new file mode 100644 index 00000000000..e32d711143d --- /dev/null +++ b/llvm/test/Transforms/SimplifyCFG/AArch64/cttz-ctlz.ll @@ -0,0 +1,43 @@ +; RUN: opt -S -simplifycfg -mtriple=aarch64 < %s | FileCheck %s + +define i32 @ctlz(i32 %A) { +; CHECK-LABEL: @ctlz( +; CHECK: [[ICMP:%[A-Za-z0-9]+]] = icmp eq i32 %A, 0 +; CHECK-NEXT: [[CTZ:%[A-Za-z0-9]+]] = tail call i32 @llvm.ctlz.i32(i32 %A, i1 true) +; CHECK-NEXT: [[SEL:%[A-Za-z0-9.]+]] = select i1 [[ICMP]], i32 32, i32 [[CTZ]] +; CHECK-NEXT: ret i32 [[SEL]] +entry: + %tobool = icmp eq i32 %A, 0 + br i1 %tobool, label %cond.end, label %cond.true + +cond.true: + %0 = tail call i32 @llvm.ctlz.i32(i32 %A, i1 true) + br label %cond.end + +cond.end: + %cond = phi i32 [ %0, %cond.true ], [ 32, %entry ] + ret i32 %cond +} + +define i32 @cttz(i32 %A) { +; CHECK-LABEL: @cttz( +; CHECK: [[ICMP:%[A-Za-z0-9]+]] = icmp eq i32 %A, 0 +; CHECK-NEXT: [[CTZ:%[A-Za-z0-9]+]] = tail call i32 @llvm.cttz.i32(i32 %A, i1 true) +; CHECK-NEXT: [[SEL:%[A-Za-z0-9.]+]] = select i1 [[ICMP]], i32 32, i32 [[CTZ]] +; CHECK-NEXT: ret i32 [[SEL]] +entry: + %tobool = icmp eq i32 %A, 0 + br i1 %tobool, label %cond.end, label %cond.true + +cond.true: + %0 = tail call i32 @llvm.cttz.i32(i32 %A, i1 true) + br label %cond.end + +cond.end: + %cond = phi i32 [ %0, %cond.true ], [ 32, %entry ] + ret i32 %cond +} + +declare i32 @llvm.ctlz.i32(i32, i1) +declare i32 @llvm.cttz.i32(i32, i1) + |
