[PULL 16/72] target/x86: Set FloatInfZeroNaNRule explicitly

[Peter Maydell]

Set the FloatInfZeroNaNRule explicitly for the x86 target.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20241202131347.498124-12-peter.maydell@linaro.org
---
 target/i386/tcg/fpu_helper.c   | 7 +++++++
 fpu/softfloat-specialize.c.inc | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/target/i386/tcg/fpu_helper.c b/target/i386/tcg/fpu_helper.c
index 53b49bb2977..3295753e075 100644
--- a/target/i386/tcg/fpu_helper.c
+++ b/target/i386/tcg/fpu_helper.c
@@ -173,6 +173,13 @@ void cpu_init_fp_statuses(CPUX86State *env)
      */
     set_float_2nan_prop_rule(float_2nan_prop_x87, &env->mmx_status);
     set_float_2nan_prop_rule(float_2nan_prop_x87, &env->sse_status);
+    /*
+     * Only SSE has multiply-add instructions. In the SDM Section 14.5.2
+     * "Fused-Multiply-ADD (FMA) Numeric Behavior" the NaN handling is
+     * specified -- for 0 * inf + NaN the input NaN is selected, and if
+     * there are multiple input NaNs they are selected in the order a, b, c.
+     */
+    set_float_infzeronan_rule(float_infzeronan_dnan_never, &env->sse_status);
 }
 
 static inline uint8_t save_exception_flags(CPUX86State *env)
diff --git a/fpu/softfloat-specialize.c.inc b/fpu/softfloat-specialize.c.inc
index 3062d19402d..ad4f7096d09 100644
--- a/fpu/softfloat-specialize.c.inc
+++ b/fpu/softfloat-specialize.c.inc
@@ -490,7 +490,7 @@ static int pickNaNMulAdd(FloatClass a_cls, FloatClass 
b_cls, FloatClass c_cls,
          * Temporarily fall back to ifdef ladder
          */
 #if defined(TARGET_HPPA) || \
-    defined(TARGET_I386) || defined(TARGET_LOONGARCH)
+    defined(TARGET_LOONGARCH)
         /*
          * For LoongArch systems that conform to IEEE754-2008, the 
(inf,zero,nan)
          * case sets InvalidOp and returns the input value 'c'
-- 
2.34.1