From: Bill Schmidt <wschmidt@linux.vnet.ibm.com>
Date: Tue, 25 Jul 2017 19:44:10 +0000 (+0000)
Subject: backport: re PR tree-optimization/81162 (UBSAN switch triggers incorrect optimization... 
X-Git-Tag: releases/gcc-5.5.0~143
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=803bdb10605c0ca118d2dc727ece1903c7aae52c;p=thirdparty%2Fgcc.git

backport: re PR tree-optimization/81162 (UBSAN switch triggers incorrect optimization in SLSR)

[gcc]

2016-07-25  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	Backport from mainline
	2016-07-14  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR tree-optimization/81162
	* gimple-ssa-strength-reduction.c (replace_mult_candidate): Don't
	replace a negate with an add.

[gcc/testsuite]

2016-07-25  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	Backport from mainline
	2016-07-14  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR tree-optimization/81162
	* gcc.dg/ubsan/pr81162.c: New file.

From-SVN: r250544
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2ace2023444d..3179d342b31c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2016-07-25  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	Backport from mainline
+	2016-07-14  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	PR tree-optimization/81162
+	* gimple-ssa-strength-reduction.c (replace_mult_candidate): Don't
+	replace a negate with an add.
+
 2017-07-24  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/80569
diff --git a/gcc/gimple-ssa-strength-reduction.c b/gcc/gimple-ssa-strength-reduction.c
index 4c4610e28d01..77c5a0508845 100644
--- a/gcc/gimple-ssa-strength-reduction.c
+++ b/gcc/gimple-ssa-strength-reduction.c
@@ -2048,13 +2048,14 @@ replace_mult_candidate (slsr_cand_t c, tree basis_name, widest_int bump)
      types but allows for safe negation without twisted logic.  */
   if (wi::fits_shwi_p (bump)
       && bump.to_shwi () != HOST_WIDE_INT_MIN
-      /* It is not useful to replace casts, copies, or adds of
+      /* It is not useful to replace casts, copies, negates, or adds of
 	 an SSA name and a constant.  */
       && cand_code != MODIFY_EXPR
       && !CONVERT_EXPR_CODE_P (cand_code)
       && cand_code != PLUS_EXPR
       && cand_code != POINTER_PLUS_EXPR
-      && cand_code != MINUS_EXPR)
+      && cand_code != MINUS_EXPR
+      && cand_code != NEGATE_EXPR)
     {
       enum tree_code code = PLUS_EXPR;
       tree bump_tree;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ba0c3fe3ce46..26a84ab89cb2 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2016-07-25  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	Backport from mainline
+	2016-07-14  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	PR tree-optimization/81162
+	* gcc.dg/ubsan/pr81162.c: New file.
+
 2017-07-24  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/80569
diff --git a/gcc/testsuite/gcc.dg/ubsan/pr81162.c b/gcc/testsuite/gcc.dg/ubsan/pr81162.c
new file mode 100644
index 000000000000..9ce98afa367d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ubsan/pr81162.c
@@ -0,0 +1,17 @@
+/* PR tree-optimization/81162 */
+/* { dg-do run } */
+/* { dg-options "-fsanitize=undefined -O2" } */
+
+short s;
+int i1 = 1;
+int i2 = 1;
+unsigned char uc = 147;
+
+int main() {
+  s = (-uc + 2147483647) << 0;
+  if (9031239389974324562ULL >= (-((i1 && i2) + uc) ^ -21096) ) {
+    return 0;
+  } else {
+    return -1;
+  }
+}