* [musl] [PATCH] math: fix fma(x,y,0) when x*y rounds to -0
@ 2024-03-13 23:57 Szabolcs Nagy
0 siblings, 0 replies; only message in thread
From: Szabolcs Nagy @ 2024-03-13 23:57 UTC (permalink / raw)
To: musl
if x!=0, y!=0, z==0 then
fma(x,y,z) == x*y
in all rounding modes, while adding z can ruin the sign of 0 if x*y
rounds to -0.
---
src/math/fma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/math/fma.c b/src/math/fma.c
index 0c6f90c9..adfadca8 100644
--- a/src/math/fma.c
+++ b/src/math/fma.c
@@ -53,7 +53,7 @@ double fma(double x, double y, double z)
return x*y + z;
if (nz.e >= ZEROINFNAN) {
if (nz.e > ZEROINFNAN) /* z==0 */
- return x*y + z;
+ return x*y;
return z;
}
--
2.43.0
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2024-03-13 23:57 [musl] [PATCH] math: fix fma(x,y,0) when x*y rounds to -0 Szabolcs Nagy
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