if (BinaryOperator *I = dyn_cast<BinaryOperator>(Val)) {
// Cannot look past anything that might overflow.
+ // We specifically require nuw because we store the Scale in an unsigned
+ // and perform an unsigned divide on it.
OverflowingBinaryOperator *OBI = dyn_cast<OverflowingBinaryOperator>(Val);
- if (OBI && !OBI->hasNoUnsignedWrap() && !OBI->hasNoSignedWrap()) {
+ if (OBI && !OBI->hasNoUnsignedWrap()) {
Scale = 1;
Offset = 0;
return Val;
; <label>:4 ; preds = %0
%5 = load i32, i32* %1, align 4
- %6 = shl nsw i32 %5, 3
-; With "nsw", the alloca and its bitcast can be fused:
- %7 = add nsw i32 %6, 2048
+ %6 = shl nuw i32 %5, 3
+; With "nuw", the alloca and its bitcast can be fused:
+ %7 = add nuw i32 %6, 2048
; CHECK: alloca double
%8 = alloca i8, i32 %7
%9 = bitcast i8* %8 to double*
; <label>:4 ; preds = %0
%5 = load i32, i32* %1, align 4
- %6 = mul nsw i32 %5, 8
-; Without "nsw", the alloca and its bitcast cannot be fused:
+ %6 = mul nuw i32 %5, 8
+; Without "nuw", the alloca and its bitcast cannot be fused:
%7 = add i32 %6, 2048
; CHECK: alloca i8
%8 = alloca i8, i32 %7
--- /dev/null
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+declare void @use(i32 *)
+
+define void @foo(i64 %X) {
+; Currently we cannot handle expressions of the form Offset - X * Scale.
+; CHECK-LABEL: @foo(
+; CHECK-NEXT: [[TMP1:%.*]] = mul nsw i64 [[X:%.*]], -4
+; CHECK-NEXT: [[TMP2:%.*]] = add nsw i64 [[TMP1]], 24
+; CHECK-NEXT: [[TMP3:%.*]] = alloca i8, i64 [[TMP2]], align 4
+; CHECK-NEXT: [[TMP4:%.*]] = bitcast i8* [[TMP3]] to i32*
+; CHECK-NEXT: call void @use(i32* nonnull [[TMP4]])
+; CHECK-NEXT: ret void
+;
+ %1 = mul nsw i64 %X, -4
+ %2 = add nsw i64 %1, 24
+ %3 = alloca i8, i64 %2, align 4
+ %4 = bitcast i8* %3 to i32*
+ call void @use(i32 *%4)
+ ret void
+}