if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZeroFP()))
return ConstantFP::getNullValue(Op0->getType());
- // sqrt(X) * sqrt(X) --> X
+ // sqrt(X) * sqrt(X) --> X, if we can:
+ // 1. Remove the intermediate rounding (reassociate).
+ // 2. Ignore non-zero negative numbers because sqrt would produce NAN.
+ // 3. Ignore -0.0 because sqrt(-0.0) == -0.0, but -0.0 * -0.0 == 0.0.
Value *X;
- if (FMF.isFast() && Op0 == Op1 &&
- match(Op0, m_Intrinsic<Intrinsic::sqrt>(m_Value(X))))
+ if (Op0 == Op1 && match(Op0, m_Intrinsic<Intrinsic::sqrt>(m_Value(X))) &&
+ FMF.allowReassoc() && FMF.noNaNs() && FMF.noSignedZeros())
return X;
return nullptr;
}
; PR21126: http://llvm.org/bugs/show_bug.cgi?id=21126
-; With unsafe/fast math, sqrt(X) * sqrt(X) is just X.
+; With loose math, sqrt(X) * sqrt(X) is just X.
declare double @llvm.sqrt.f64(double)
; CHECK-NEXT: ret double [[F:%.*]]
;
%sqrt = call double @llvm.sqrt.f64(double %f)
- %mul = fmul fast double %sqrt, %sqrt
+ %mul = fmul reassoc nnan nsz double %sqrt, %sqrt
+ ret double %mul
+}
+
+; Negative tests for the above transform: we need all 3 of those flags.
+
+define double @sqrt_squared_not_fast_enough1(double %f) {
+; CHECK-LABEL: @sqrt_squared_not_fast_enough1(
+; CHECK-NEXT: [[SQRT:%.*]] = call double @llvm.sqrt.f64(double [[F:%.*]])
+; CHECK-NEXT: [[MUL:%.*]] = fmul nnan nsz double [[SQRT]], [[SQRT]]
+; CHECK-NEXT: ret double [[MUL]]
+;
+ %sqrt = call double @llvm.sqrt.f64(double %f)
+ %mul = fmul nnan nsz double %sqrt, %sqrt
+ ret double %mul
+}
+
+define double @sqrt_squared_not_fast_enough2(double %f) {
+; CHECK-LABEL: @sqrt_squared_not_fast_enough2(
+; CHECK-NEXT: [[SQRT:%.*]] = call double @llvm.sqrt.f64(double [[F:%.*]])
+; CHECK-NEXT: [[MUL:%.*]] = fmul reassoc nnan double [[SQRT]], [[SQRT]]
+; CHECK-NEXT: ret double [[MUL]]
+;
+ %sqrt = call double @llvm.sqrt.f64(double %f)
+ %mul = fmul reassoc nnan double %sqrt, %sqrt
+ ret double %mul
+}
+
+define double @sqrt_squared_not_fast_enough3(double %f) {
+; CHECK-LABEL: @sqrt_squared_not_fast_enough3(
+; CHECK-NEXT: [[SQRT:%.*]] = call double @llvm.sqrt.f64(double [[F:%.*]])
+; CHECK-NEXT: [[MUL:%.*]] = fmul reassoc nsz double [[SQRT]], [[SQRT]]
+; CHECK-NEXT: ret double [[MUL]]
+;
+ %sqrt = call double @llvm.sqrt.f64(double %f)
+ %mul = fmul reassoc nsz double %sqrt, %sqrt
ret double %mul
}