From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 30 May 2017 07:23:20 +0000 (+0200)
Subject: backport: re PR middle-end/77594 (double computation for __builtin_sub_overflow ... 
X-Git-Tag: releases/gcc-5.5.0~303
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=77fe8048b2d91dd3385c9685d9a8996f7d563f02;p=thirdparty%2Fgcc.git

backport: re PR middle-end/77594 (double computation for __builtin_sub_overflow (0, ...))

	Backported from mainline
	2016-09-16  Jakub Jelinek  <jakub@redhat.com>
		    Eric Botcazou  <ebotcazou@adacore.com>

	PR middle-end/77594
	* internal-fn.c (expand_arith_overflow) <case MINUS_EXPR>: Don't fall
	through into expand_addsub_overflow after expand_neg_overflow.

	* gcc.target/i386/pr77594.c: New test.

From-SVN: r248607
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3fc433d85395..855c5a642c1a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,13 @@
 2017-05-30  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2016-09-16  Jakub Jelinek  <jakub@redhat.com>
+		    Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR middle-end/77594
+	* internal-fn.c (expand_arith_overflow) <case MINUS_EXPR>: Don't fall
+	through into expand_addsub_overflow after expand_neg_overflow.
+
 	2016-09-14  Jakub Jelinek  <jakub@redhat.com>
 
 	PR sanitizer/68260
diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c
index e4028250c2ac..2da980512fcb 100644
--- a/gcc/internal-fn.c
+++ b/gcc/internal-fn.c
@@ -1786,7 +1786,10 @@ expand_arith_overflow (enum tree_code code, gimple stmt)
 	    {
 	    case MINUS_EXPR:
 	      if (integer_zerop (arg0) && !unsr_p)
-		expand_neg_overflow (loc, lhs, arg1, false);
+		{
+		  expand_neg_overflow (loc, lhs, arg1, false);
+		  return;
+		}
 	      /* FALLTHRU */
 	    case PLUS_EXPR:
 	      expand_addsub_overflow (loc, code, lhs, arg0, arg1,
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 468bd1d3a45d..8618807b782c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,12 @@
 2017-05-30  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2016-09-16  Jakub Jelinek  <jakub@redhat.com>
+		    Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR middle-end/77594
+	* gcc.target/i386/pr77594.c: New test.
+
 	2016-09-14  Jakub Jelinek  <jakub@redhat.com>
 
 	PR sanitizer/68260
diff --git a/gcc/testsuite/gcc.target/i386/pr77594.c b/gcc/testsuite/gcc.target/i386/pr77594.c
new file mode 100644
index 000000000000..96c51fd71fa2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr77594.c
@@ -0,0 +1,11 @@
+/* PR middle-end/77594 */
+/* { dg-do compile } */
+/* { dg-options "-O0" } */
+
+int
+foo (int a, int *b)
+{
+  return __builtin_sub_overflow (0, a, b);
+}
+
+/* { dg-final { scan-assembler-times "\tjn?o\t" 1 } } */