...
%367 = icmp eq i32 %362, 0 ; [#uses=1]
-
-//===---------------------------------------------------------------------===//
-
-Missed instcombine/dagcombine transformation:
-define i32 @a(i32 %x, i32 %y) nounwind readnone {
-entry:
- %mul = mul i32 %y, -8
- %sub = sub i32 %x, %mul
- ret i32 %sub
-}
-
-Should compile to something like x+y*8, but currently compiles to an
-inefficient result. Testcase derived from gcc. C testcase:
-
-int a(int x, int y) { return y-x*-8; }
-
//===---------------------------------------------------------------------===//
Missed instcombine/dagcombine transformation:
C2);
return BinaryOperator::CreateMul(Op0, CP1);
}
+
+ // X - A*-B -> X + A*B
+ // X - -A*B -> X + A*B
+ Value *A, *B;
+ if (match(Op1I, m_Mul(m_Value(A), m_Neg(m_Value(B)))) ||
+ match(Op1I, m_Mul(m_Neg(m_Value(A)), m_Value(B)))) {
+ Value *NewMul = Builder->CreateMul(A, B);
+ return BinaryOperator::CreateAdd(Op0, NewMul);
+ }
}
}
; CHECK-NEXT: ret i32
}
+define i32 @test27(i32 %x, i32 %y) {
+ %mul = mul i32 %y, -8
+ %sub = sub i32 %x, %mul
+ ret i32 %sub
+; CHECK: @test27
+; CHECK-NEXT: shl i32 %y, 3
+; CHECK-NEXT: add i32
+; CHECK-NEXT: ret i32
+}
+
+define i32 @test28(i32 %x, i32 %y, i32 %z) {
+ %neg = sub i32 0, %z
+ %mul = mul i32 %neg, %y
+ %sub = sub i32 %x, %mul
+ ret i32 %sub
+; CHECK: @test28
+; CHECK-NEXT: mul i32 %z, %y
+; CHECK-NEXT: add i32
+; CHECK-NEXT: ret i32
+}