From bc92c260f6f0da73d3bdee5e1c2bf38d6f22e20a Mon Sep 17 00:00:00 2001
From: Giuseppe Musacchio <thatlemon@gmail.com>
Date: Fri, 13 Nov 2020 00:01:29 +0100
Subject: [PATCH] ppc/translate: Delay NaN checking after comparison

Since we always perform a comparison between the two operands avoid
checking for NaN unless the result states they're unordered.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Giuseppe Musacchio <thatlemon@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201112230130.65262-4-thatlemon@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 target/ppc/fpu_helper.c | 80 +++++++++++++++++++++--------------------
 1 file changed, 42 insertions(+), 38 deletions(-)

diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
index 34f5bc1f3c..f5a4be595a 100644
--- a/target/ppc/fpu_helper.c
+++ b/target/ppc/fpu_helper.c
@@ -2475,25 +2475,6 @@ static inline void do_scalar_cmp(CPUPPCState *env, ppc_vsr_t *xa, ppc_vsr_t *xb,
 
     helper_reset_fpstatus(env);
 
-    if (float64_is_signaling_nan(xa->VsrD(0), &env->fp_status) ||
-        float64_is_signaling_nan(xb->VsrD(0), &env->fp_status)) {
-        vxsnan_flag = true;
-        if (fpscr_ve == 0 && ordered) {
-            vxvc_flag = true;
-        }
-    } else if (float64_is_quiet_nan(xa->VsrD(0), &env->fp_status) ||
-               float64_is_quiet_nan(xb->VsrD(0), &env->fp_status)) {
-        if (ordered) {
-            vxvc_flag = true;
-        }
-    }
-    if (vxsnan_flag) {
-        float_invalid_op_vxsnan(env, GETPC());
-    }
-    if (vxvc_flag) {
-        float_invalid_op_vxvc(env, 0, GETPC());
-    }
-
     switch (float64_compare(xa->VsrD(0), xb->VsrD(0), &env->fp_status)) {
     case float_relation_less:
         cc = CRF_LT;
@@ -2506,6 +2487,27 @@ static inline void do_scalar_cmp(CPUPPCState *env, ppc_vsr_t *xa, ppc_vsr_t *xb,
         break;
     case float_relation_unordered:
         cc = CRF_SO;
+
+        if (float64_is_signaling_nan(xa->VsrD(0), &env->fp_status) ||
+            float64_is_signaling_nan(xb->VsrD(0), &env->fp_status)) {
+            vxsnan_flag = true;
+            if (fpscr_ve == 0 && ordered) {
+                vxvc_flag = true;
+            }
+        } else if (float64_is_quiet_nan(xa->VsrD(0), &env->fp_status) ||
+                   float64_is_quiet_nan(xb->VsrD(0), &env->fp_status)) {
+            if (ordered) {
+                vxvc_flag = true;
+            }
+        }
+
+        if (vxsnan_flag) {
+            float_invalid_op_vxsnan(env, GETPC());
+        }
+        if (vxvc_flag) {
+            float_invalid_op_vxvc(env, 0, GETPC());
+        }
+
         break;
     default:
         g_assert_not_reached();
@@ -2538,25 +2540,6 @@ static inline void do_scalar_cmpq(CPUPPCState *env, ppc_vsr_t *xa,
 
     helper_reset_fpstatus(env);
 
-    if (float128_is_signaling_nan(xa->f128, &env->fp_status) ||
-        float128_is_signaling_nan(xb->f128, &env->fp_status)) {
-        vxsnan_flag = true;
-        if (fpscr_ve == 0 && ordered) {
-            vxvc_flag = true;
-        }
-    } else if (float128_is_quiet_nan(xa->f128, &env->fp_status) ||
-               float128_is_quiet_nan(xb->f128, &env->fp_status)) {
-        if (ordered) {
-            vxvc_flag = true;
-        }
-    }
-    if (vxsnan_flag) {
-        float_invalid_op_vxsnan(env, GETPC());
-    }
-    if (vxvc_flag) {
-        float_invalid_op_vxvc(env, 0, GETPC());
-    }
-
     switch (float128_compare(xa->f128, xb->f128, &env->fp_status)) {
     case float_relation_less:
         cc = CRF_LT;
@@ -2569,6 +2552,27 @@ static inline void do_scalar_cmpq(CPUPPCState *env, ppc_vsr_t *xa,
         break;
     case float_relation_unordered:
         cc = CRF_SO;
+
+        if (float128_is_signaling_nan(xa->f128, &env->fp_status) ||
+            float128_is_signaling_nan(xb->f128, &env->fp_status)) {
+            vxsnan_flag = true;
+            if (fpscr_ve == 0 && ordered) {
+                vxvc_flag = true;
+            }
+        } else if (float128_is_quiet_nan(xa->f128, &env->fp_status) ||
+                   float128_is_quiet_nan(xb->f128, &env->fp_status)) {
+            if (ordered) {
+                vxvc_flag = true;
+            }
+        }
+
+        if (vxsnan_flag) {
+            float_invalid_op_vxsnan(env, GETPC());
+        }
+        if (vxvc_flag) {
+            float_invalid_op_vxvc(env, 0, GETPC());
+        }
+
         break;
     default:
         g_assert_not_reached();