to do this and more, but would only do it if X/Y had only one use. Spotted as the
most common missed simplification in SPEC by my auto-simplifier, now that it knows
about nuw/nsw/exact flags. This removes a bunch of multiplications from 447.dealII
and 483.xalancbmk. It also removes a lot from tramp3d-v4, which results in much
more inlining.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124560
91177308-0d34-0410-b5e6-
96231b3b80d8
if (match(Op1, m_One()))
return Op0;
+ // (X / Y) * Y -> X if the division is exact.
+ Value *X = 0, *Y = 0;
+ if ((match(Op0, m_SDiv(m_Value(X), m_Value(Y))) && Y == Op1) || // (X / Y) * Y
+ (match(Op1, m_SDiv(m_Value(X), m_Value(Y))) && Y == Op0)) { // Y * (X / Y)
+ BinaryOperator *SDiv = cast<BinaryOperator>(Y == Op1 ? Op0 : Op1);
+ if (SDiv->isExact())
+ return X;
+ }
+
// i1 mul -> and.
if (MaxRecurse && Op0->getType()->isIntegerTy(1))
if (Value *V = SimplifyAndInst(Op0, Op1, TD, DT, MaxRecurse-1))
; CHECK: ret i32 0
}
+define i32 @sdiv4(i32 %x, i32 %y) {
+; CHECK: @sdiv4
+; (X / Y) * Y -> X if the division is exact
+ %div = sdiv exact i32 %x, %y
+ %mul = mul i32 %div, %y
+ ret i32 %mul
+; CHECK: ret i32 %x
+}
+
+define i32 @sdiv5(i32 %x, i32 %y) {
+; CHECK: @sdiv5
+; Y * (X / Y) -> X if the division is exact
+ %div = sdiv exact i32 %x, %y
+ %mul = mul i32 %y, %div
+ ret i32 %mul
+; CHECK: ret i32 %x
+}
+
define i32 @udiv1(i32 %x, i32 %y) {
; CHECK: @udiv1
; (no overflow X * Y) / Y -> X