Fix mul expansion to check the correct number of bits for

zero extension when checking if an unsigned multiply is
safe.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48171 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index abd569b208edaa9ae6a217bfd1d5d4f475f06616..1ef19ff50fa8db71ec43ab7650a3590477324153 100644 (file)
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -6436,10 +6436,9 @@ void SelectionDAGLegalize::ExpandOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi){
       unsigned InnerBitSize = RH.getValueSizeInBits();
       unsigned LHSSB = DAG.ComputeNumSignBits(Op.getOperand(0));
       unsigned RHSSB = DAG.ComputeNumSignBits(Op.getOperand(1));
-      if (DAG.MaskedValueIsZero(Op.getOperand(0),
-                                APInt::getHighBitsSet(OuterBitSize, LHSSB)) &&
-          DAG.MaskedValueIsZero(Op.getOperand(1),
-                                APInt::getHighBitsSet(OuterBitSize, RHSSB))) {
+      APInt HighMask = APInt::getHighBitsSet(OuterBitSize, InnerBitSize);
+      if (DAG.MaskedValueIsZero(Node->getOperand(0), HighMask) &&
+          DAG.MaskedValueIsZero(Node->getOperand(1), HighMask)) {
         // The inputs are both zero-extended.
         if (HasUMUL_LOHI) {
           // We can emit a umul_lohi.

diff --git a/test/CodeGen/X86/mul-legalize.ll b/test/CodeGen/X86/mul-legalize.ll
new file mode 100644 (file)
index 0000000..b3f9cd8
--- /dev/null
+++ b/test/CodeGen/X86/mul-legalize.ll
@@ -0,0 +1,27 @@
+; RUN: llvm-as < %s | llc -march=x86 | grep cmov | count 1
+; PR2135
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
+target triple = "i386-pc-linux-gnu"
+@.str = constant [13 x i8] c"c45531m.adb\00\00"                
+
+define void @main() {
+entry:
+       %tmp1 = call i1 @report__equal( i32 3, i32 3 )          
+       %b.0 = select i1 %tmp1, i64 35184372088832, i64 0               
+       %tmp7 = mul i64 3, %b.0         
+       %tmp32 = icmp eq i64 %tmp7, 105553116266496             
+       br i1 %tmp32, label %return, label %bb35
+bb35:          
+       call void @abort( )
+       unreachable
+return:                
+       ret void
+}
+
+define i1 @report__equal(i32 %x, i32 %y) {
+       %tmp = icmp eq i32 %x, %y               
+       ret i1 %tmp
+}
+
+declare void @abort()