From b40eec96b26028b68c3594fbf34b6d6f029df26a Mon Sep 17 00:00:00 2001
From: Joseph Myers
Date: Thu, 7 May 2020 00:44:57 +0000
Subject: target/i386: fix fscale handling of invalid exponent encodings

The fscale implementation does not check for invalid encodings in the
exponent operand, thus treating them like INT_MIN (the value returned
for invalid encodings by floatx80_to_int32_round_to_zero).  Fix it to
treat them similarly to signaling NaN exponents, thus generating a
quiet NaN result.

Signed-off-by: Joseph Myers <joseph@codesourcery.com>
Message-Id: <alpine.DEB.2.21.2005070044190.18350@digraph.polyomino.org.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 tests/tcg/i386/test-i386-fscale.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

(limited to 'tests/tcg/i386')

diff --git a/tests/tcg/i386/test-i386-fscale.c b/tests/tcg/i386/test-i386-fscale.c
index aecac5125f..b65a055d0a 100644
--- a/tests/tcg/i386/test-i386-fscale.c
+++ b/tests/tcg/i386/test-i386-fscale.c
@@ -8,6 +8,11 @@ union u {
     long double ld;
 };
 
+volatile union u ld_invalid_1 = { .s = { 1, 1234 } };
+volatile union u ld_invalid_2 = { .s = { 0, 1234 } };
+volatile union u ld_invalid_3 = { .s = { 0, 0x7fff } };
+volatile union u ld_invalid_4 = { .s = { (UINT64_C(1) << 63) - 1, 0x7fff } };
+
 volatile long double ld_res;
 
 int isnan_ld(long double x)
@@ -33,5 +38,29 @@ int main(void)
         printf("FAIL: fscale snan\n");
         ret = 1;
     }
+    __asm__ volatile ("fscale" : "=t" (ld_res) :
+                      "0" (2.5L), "u" (ld_invalid_1.ld));
+    if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
+        printf("FAIL: fscale invalid 1\n");
+        ret = 1;
+    }
+    __asm__ volatile ("fscale" : "=t" (ld_res) :
+                      "0" (2.5L), "u" (ld_invalid_2.ld));
+    if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
+        printf("FAIL: fscale invalid 2\n");
+        ret = 1;
+    }
+    __asm__ volatile ("fscale" : "=t" (ld_res) :
+                      "0" (2.5L), "u" (ld_invalid_3.ld));
+    if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
+        printf("FAIL: fscale invalid 3\n");
+        ret = 1;
+    }
+    __asm__ volatile ("fscale" : "=t" (ld_res) :
+                      "0" (2.5L), "u" (ld_invalid_4.ld));
+    if (!isnan_ld(ld_res) || issignaling_ld(ld_res)) {
+        printf("FAIL: fscale invalid 4\n");
+        ret = 1;
+    }
     return ret;
 }
-- 
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