Merge pull request #286 from hvdijk/avoid-fma-ub

Avoid undefined behavior in FMA.
uxlfoundation · Jan 9, 2024 · 400c4cb · 400c4cb
2 parents ce793d3 + 14ed452
commit 400c4cb
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/modules/compiler/builtins/abacus/source/abacus_math/fma.cpp b/modules/compiler/builtins/abacus/source/abacus_math/fma.cpp
@@ -432,7 +432,7 @@ T ABACUS_API __abacus_fma_unsafe(const T x, const T y, const T z) {
   const SignedType finalExpBiased =
       (((ansAsUint & exp_mask) >> mantissa_bits)) + 2 * ansExp;
 
-  if (finalExpBiased < 1) {
+  if (ans != 0 && finalExpBiased < 1) {
     // The answer is a denormal, find what bits will be cut off and see if it's
     // going to result in a RTE case.
     const UnsignedType rounding_bits = UnsignedType(0x1)