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102 lines
3.2 KiB
102 lines
3.2 KiB
From a280a700fb016178776cb599d8cf918185df8697 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@redhat.com>
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Date: Tue, 23 May 2023 12:34:33 +0200
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Subject: [PATCH 11/22] target/s390x: Fix determination of overflow condition
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code after subtraction
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Cédric Le Goater <clg@redhat.com>
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RH-MergeRequest: 279: Backport latest s390x-related fixes from upstream QEMU for qemu-kvm in RHEL 8.9
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RH-Bugzilla: 2169308 2209605
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RH-Acked-by: Thomas Huth <thuth@redhat.com>
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RH-Acked-by: David Hildenbrand <david@redhat.com>
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RH-Acked-by: Cornelia Huck <cohuck@redhat.com>
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RH-Commit: [10/21] 14792faddfca784503f89c292ebaba5be8d3fc96
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Bugzilla: https://bugzilla.redhat.com/2169308
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commit fc6e0d0f2db5126592bb4066d484fcdfc14ccf36
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Author: Bruno Haible <bruno@clisp.org>
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Date: Wed Mar 23 17:26:21 2022 +0100
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target/s390x: Fix determination of overflow condition code after subtraction
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Reported by Paul Eggert in
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https://lists.gnu.org/archive/html/bug-gnulib/2021-09/msg00050.html
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This program currently prints different results when run with TCG instead
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of running on real s390x hardware:
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#include <stdio.h>
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int overflow_32 (int x, int y)
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{
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int sum;
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return __builtin_sub_overflow (x, y, &sum);
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}
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int overflow_64 (long long x, long long y)
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{
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long sum;
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return __builtin_sub_overflow (x, y, &sum);
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}
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int a1 = 0;
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int b1 = -2147483648;
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long long a2 = 0L;
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long long b2 = -9223372036854775808L;
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int main ()
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{
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{
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int a = a1;
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int b = b1;
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printf ("a = 0x%x, b = 0x%x\n", a, b);
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printf ("no_overflow = %d\n", ! overflow_32 (a, b));
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}
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{
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long long a = a2;
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long long b = b2;
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printf ("a = 0x%llx, b = 0x%llx\n", a, b);
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printf ("no_overflow = %d\n", ! overflow_64 (a, b));
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}
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}
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Signed-off-by: Bruno Haible <bruno@clisp.org>
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Resolves: https://gitlab.com/qemu-project/qemu/-/issues/618
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Message-Id: <20220323162621.139313-3-thuth@redhat.com>
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Signed-off-by: Thomas Huth <thuth@redhat.com>
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Signed-off-by: Cédric Le Goater <clg@redhat.com>
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---
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target/s390x/tcg/cc_helper.c | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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diff --git a/target/s390x/tcg/cc_helper.c b/target/s390x/tcg/cc_helper.c
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index e11cdb745d..b2e8d3d9f5 100644
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--- a/target/s390x/tcg/cc_helper.c
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+++ b/target/s390x/tcg/cc_helper.c
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@@ -151,7 +151,7 @@ static uint32_t cc_calc_add_64(int64_t a1, int64_t a2, int64_t ar)
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static uint32_t cc_calc_sub_64(int64_t a1, int64_t a2, int64_t ar)
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{
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- if ((a1 > 0 && a2 < 0 && ar < 0) || (a1 < 0 && a2 > 0 && ar > 0)) {
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+ if ((a1 >= 0 && a2 < 0 && ar < 0) || (a1 < 0 && a2 > 0 && ar > 0)) {
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return 3; /* overflow */
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} else {
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if (ar < 0) {
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@@ -211,7 +211,7 @@ static uint32_t cc_calc_add_32(int32_t a1, int32_t a2, int32_t ar)
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static uint32_t cc_calc_sub_32(int32_t a1, int32_t a2, int32_t ar)
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{
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- if ((a1 > 0 && a2 < 0 && ar < 0) || (a1 < 0 && a2 > 0 && ar > 0)) {
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+ if ((a1 >= 0 && a2 < 0 && ar < 0) || (a1 < 0 && a2 > 0 && ar > 0)) {
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return 3; /* overflow */
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} else {
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if (ar < 0) {
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--
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2.37.3
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