Don't generate sbfx / ubfx with negative lsb field. Patch by David Conrad.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84813 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 6e97693..5c1835b 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -1287,7 +1287,7 @@
assert(Srl_imm > 0 && Srl_imm < 32 && "bad amount in shift node!");
unsigned Width = 32 - Srl_imm;
int LSB = Srl_imm - Shl_imm;
- if ((LSB + Width) > 32)
+ if (LSB < 0)
return NULL;
SDValue Reg0 = CurDAG->getRegister(0, MVT::i32);
SDValue Ops[] = { Op.getOperand(0).getOperand(0),
diff --git a/test/CodeGen/ARM/sbfx.ll b/test/CodeGen/ARM/sbfx.ll
index 923f52a..6f1d87d 100644
--- a/test/CodeGen/ARM/sbfx.ll
+++ b/test/CodeGen/ARM/sbfx.ll
@@ -35,3 +35,13 @@
%tmp2 = lshr i32 %tmp, 29
ret i32 %tmp2
}
+
+define i32 @f5(i32 %a) {
+entry:
+; CHECK: f5:
+; CHECK-NOT: sbfx
+; CHECK: bx
+ %tmp = shl i32 %a, 3
+ %tmp2 = ashr i32 %tmp, 1
+ ret i32 %tmp2
+}