Remove an incorrect overaggressive optimization

(PPC specific).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89496 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index fb9a2409e7165e9eacc90e550ba4692d5183caf1..1cdd51e9fe2ea0e111546d5c975b8253752ba534 100644 (file)
--- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -443,8 +443,7 @@ SDNode *PPCDAGToDAGISel::SelectBitfieldInsert(SDNode *N) {
     
     unsigned MB, ME;
     if (InsertMask && isRunOfOnes(InsertMask, MB, ME)) {
-      SDValue Tmp1, Tmp2, Tmp3;
-      bool DisjointMask = (TargetMask ^ InsertMask) == 0xFFFFFFFF;
+      SDValue Tmp1, Tmp2;
 
       if ((Op1Opc == ISD::SHL || Op1Opc == ISD::SRL) &&
           isInt32Immediate(Op1.getOperand(1), Value)) {
@@ -461,10 +460,9 @@ SDNode *PPCDAGToDAGISel::SelectBitfieldInsert(SDNode *N) {
           Op1 = Op1.getOperand(0);
         }
       }
-      
-      Tmp3 = (Op0Opc == ISD::AND && DisjointMask) ? Op0.getOperand(0) : Op0;
+
       SH &= 31;
-      SDValue Ops[] = { Tmp3, Op1, getI32Imm(SH), getI32Imm(MB),
+      SDValue Ops[] = { Op0, Op1, getI32Imm(SH), getI32Imm(MB),
                           getI32Imm(ME) };
       return CurDAG->getMachineNode(PPC::RLWIMI, dl, MVT::i32, Ops, 5);
     }

diff --git a/test/CodeGen/PowerPC/rlwimi-keep-rsh.ll b/test/CodeGen/PowerPC/rlwimi-keep-rsh.ll
new file mode 100644 (file)
index 0000000..7bce01c
--- /dev/null
+++ b/test/CodeGen/PowerPC/rlwimi-keep-rsh.ll
@@ -0,0 +1,28 @@
+; RUN: llc < %s -march=ppc32 -mtriple=powerpc-apple-darwin | FileCheck %s
+; Formerly dropped the RHS of %tmp6 when constructing rlwimi.
+; 7346117
+
+@foo = external global i32
+
+define void @xxx(i32 %a, i32 %b, i32 %c, i32 %d) nounwind optsize {
+; CHECK: _xxx:
+; CHECK: or
+; CHECK: and
+; CHECK: rlwimi
+entry:
+  %tmp0 = ashr i32 %d, 31
+  %tmp1 = and i32 %tmp0, 255
+  %tmp2 = xor i32 %tmp1, 255
+  %tmp3 = ashr i32 %b, 31
+  %tmp4 = ashr i32 %a, 4
+  %tmp5 = or i32 %tmp3, %tmp4
+  %tmp6 = and i32 %tmp2, %tmp5
+  %tmp7 = shl i32 %c, 8
+  %tmp8 = or i32 %tmp6, %tmp7
+  store i32 %tmp8, i32* @foo, align 4
+  br label %return
+
+return:
+  ret void
+; CHECK: blr
+}
\ No newline at end of file