[APFloat] Prevent construction of APFloat with Semantics and FP value

Constructor invocations such as `APFloat(APFloat::IEEEdouble(), 0.0)`
may seem like they accept a FP (floating point) value, but the overload
they reach is actually the `integerPart` one, not a `float` or `double`
overload (which only exists when `fltSemantics` isn't passed).

This may lead to possible loss of data, by the conversion from `float`
or `double` to `integerPart`.

To prevent future mistakes, a new constructor overload, which accepts
any FP value and marked with `delete`, to prevent its usage.

Fixes PR34095.

Differential Revision: https://reviews.llvm.org/D70425

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index ef2af01f8af..44513b1f682 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -1735,7 +1735,7 @@ Value *LibCallSimplifier::optimizePow(CallInst *Pow, IRBuilder<> &B) {
     // TODO: This whole transformation should be backend specific (e.g. some
     //       backends might prefer libcalls or the limit for the exponent might
     //       be different) and it should also consider optimizing for size.
-    APFloat LimF(ExpoF->getSemantics(), 33.0),
+    APFloat LimF(ExpoF->getSemantics(), 33),
             ExpoA(abs(*ExpoF));
     if (ExpoA.compare(LimF) == APFloat::cmpLessThan) {
       // This transformation applies to integer or integer+0.5 exponents only.