Fix an off-by-one error in ctpop combining.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123664 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 1621d61ba9be9e2357727b6985379fba908c6401..514f175ee092bc580820f87e5492fba182ef03d9 100644 (file)
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1876,7 +1876,7 @@ TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
       CTPOP = N0.getOperand(0);
 
     if (CTPOP.hasOneUse() && CTPOP.getOpcode() == ISD::CTPOP &&
-        (N0 == CTPOP || N0.getValueType().getSizeInBits() >=
+        (N0 == CTPOP || N0.getValueType().getSizeInBits() >
                         Log2_32_Ceil(CTPOP.getValueType().getSizeInBits()))) {
       EVT CTVT = CTPOP.getValueType();
       SDValue CTOp = CTPOP.getOperand(0);

diff --git a/test/CodeGen/X86/ctpop-combine.ll b/test/CodeGen/X86/ctpop-combine.ll
index b87637f9424fc6de6950d0d65e5ca29b7d7231e4..c957d385a24a14d59e7f6b6bc8ab8646811428c7 100644 (file)
--- a/test/CodeGen/X86/ctpop-combine.ll
+++ b/test/CodeGen/X86/ctpop-combine.ll
@@ -18,8 +18,7 @@ define i32 @test1(i64 %x) nounwind readnone {
 
 define i32 @test2(i64 %x) nounwind readnone {
   %count = tail call i64 @llvm.ctpop.i64(i64 %x)
-  %cast = trunc i64 %count to i32
-  %cmp = icmp ult i32 %cast, 2
+  %cmp = icmp ult i64 %count, 2
   %conv = zext i1 %cmp to i32
   ret i32 %conv
 ; CHECK: test2:
@@ -29,3 +28,13 @@ define i32 @test2(i64 %x) nounwind readnone {
 ; CHECK: ret
 }
 
+define i32 @test3(i64 %x) nounwind readnone {
+  %count = tail call i64 @llvm.ctpop.i64(i64 %x)
+  %cast = trunc i64 %count to i6 ; Too small for 0-64
+  %cmp = icmp ult i6 %cast, 2
+  %conv = zext i1 %cmp to i32
+  ret i32 %conv
+; CHECK: test3:
+; CHECK: cmpb $2
+; CHECK: ret
+}