llvm-6502/test/CodeGen/PowerPC/cttz-ctlz-spec.ll
Hal Finkel 0ef8f3189e [PowerPC] Enable speculation of cttz/ctlz
PPC has an instruction for ctlz with defined zero behavior, and our lowering of
cttz (provided by DAGCombine) is also efficient and branchless, so speculating
these makes sense.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225150 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-05 05:24:42 +00:00

42 lines
1.3 KiB
LLVM

; RUN: opt -S -codegenprepare < %s | FileCheck %s
target datalayout = "E-m:e-i64:64-n32:64"
target triple = "powerpc64-unknown-linux-gnu"
define i64 @test1(i64 %A) {
; CHECK-LABEL: @test1(
; CHECK: [[CTLZ:%[A-Za-z0-9]+]] = call i64 @llvm.ctlz.i64(i64 %A, i1 false)
; CHECK-NEXT: ret i64 [[CTLZ]]
entry:
%tobool = icmp eq i64 %A, 0
br i1 %tobool, label %cond.end, label %cond.true
cond.true: ; preds = %entry
%0 = tail call i64 @llvm.ctlz.i64(i64 %A, i1 true)
br label %cond.end
cond.end: ; preds = %entry, %cond.true
%cond = phi i64 [ %0, %cond.true ], [ 64, %entry ]
ret i64 %cond
}
define i64 @test1b(i64 %A) {
; CHECK-LABEL: @test1b(
; CHECK: [[CTTZ:%[A-Za-z0-9]+]] = call i64 @llvm.cttz.i64(i64 %A, i1 false)
; CHECK-NEXT: ret i64 [[CTTZ]]
entry:
%tobool = icmp eq i64 %A, 0
br i1 %tobool, label %cond.end, label %cond.true
cond.true: ; preds = %entry
%0 = tail call i64 @llvm.cttz.i64(i64 %A, i1 true)
br label %cond.end
cond.end: ; preds = %entry, %cond.true
%cond = phi i64 [ %0, %cond.true ], [ 64, %entry ]
ret i64 %cond
}
declare i64 @llvm.ctlz.i64(i64, i1)
declare i64 @llvm.cttz.i64(i64, i1)