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[InstCombine] Add test cases for opportunities to improve knownbits handling for cttz and ctlz intrinsics. 

llvm-svn: 301385
This commit is contained in:
Craig Topper 2017-04-26 05:59:19 +00:00
parent e3986c544d
commit 17a2b694c0
1 changed files with 26 additions and 0 deletions
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26
llvm/test/Transforms/InstCombine/intrinsics.ll
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@ -281,6 +281,19 @@ define i32 @cttz(i32 %a) {
ret i32 %count
}
define i1 @cttz_knownbits(i32 %arg) {
; CHECK-LABEL: @cttz_knownbits(
; CHECK-NEXT: [[OR:%.*]] = or i32 [[ARG:%.*]], 4
; CHECK-NEXT: [[CNT:%.*]] = call i32 @llvm.cttz.i32(i32 [[OR]], i1 true) #0
; CHECK-NEXT: [[RES:%.*]] = icmp eq i32 [[CNT]], 4
; CHECK-NEXT: ret i1 [[RES]]
;
%or = or i32 %arg, 4
%cnt = call i32 @llvm.cttz.i32(i32 %or, i1 true) nounwind readnone
%res = icmp eq i32 %cnt, 4
ret i1 %res
}
define i8 @ctlz(i8 %a) {
; CHECK-LABEL: @ctlz(
; CHECK-NEXT: ret i8 2
@ -291,6 +304,19 @@ define i8 @ctlz(i8 %a) {
ret i8 %count
}
define i1 @ctlz_knownbits(i8 %arg) {
; CHECK-LABEL: @ctlz_knownbits(
; CHECK-NEXT: [[OR:%.*]] = or i8 [[ARG:%.*]], 32
; CHECK-NEXT: [[CNT:%.*]] = call i8 @llvm.ctlz.i8(i8 [[OR]], i1 true) #0
; CHECK-NEXT: [[RES:%.*]] = icmp eq i8 [[CNT]], 4
; CHECK-NEXT: ret i1 [[RES]]
;
%or = or i8 %arg, 32
%cnt = call i8 @llvm.ctlz.i8(i8 %or, i1 true) nounwind readnone
%res = icmp eq i8 %cnt, 4
ret i1 %res
}
define void @cmp.simplify(i32 %a, i32 %b, i1* %c) {
%lz = tail call i32 @llvm.ctlz.i32(i32 %a, i1 false) nounwind readnone
%lz.cmp = icmp eq i32 %lz, 32