[llvm] r301385 - [InstCombine] Add test cases for opportunities to improve knownbits handling for cttz and ctlz intrinsics.

[Craig Topper via llvm-commits]

Author: ctopper
Date: Wed Apr 26 00:59:19 2017
New Revision: 301385

URL: http://llvm.org/viewvc/llvm-project?rev=301385&view=rev
Log:
[InstCombine] Add test cases for opportunities to improve knownbits handling for cttz and ctlz intrinsics.

Modified:
    llvm/trunk/test/Transforms/InstCombine/intrinsics.ll

Modified: llvm/trunk/test/Transforms/InstCombine/intrinsics.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/intrinsics.ll?rev=301385&r1=301384&r2=301385&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/intrinsics.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/intrinsics.ll Wed Apr 26 00:59:19 2017
@@ -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