From: Richard Biener <rguenther@suse.de>
Date: Fri, 15 Jul 2016 12:56:17 +0000 (+0000)
Subject: re PR tree-optimization/71887 (wrong code (SIGFPE) at -O1 and above on x86_64-linux... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9513d5fbcabaf84b5e8450e8bb16894b3d42ba96;p=gcc.git

re PR tree-optimization/71887 (wrong code (SIGFPE) at -O1 and above on x86_64-linux-gnu (in both 32-bit and 64-bit modes))

2016-07-15  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/71887
	* tree-ssa-phiopt.c (absorbing_element_p): Add rhs arg and
	verify it is not zero for division / modulo handling.
	(value_replacement): Adjust.

	* gcc.dg/torture/pr71887.c: New testcase.

From-SVN: r238373
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index dc1d9ee9872..318baa20411 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2016-07-15  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/71887
+	* tree-ssa-phiopt.c (absorbing_element_p): Add rhs arg and
+	verify it is not zero for division / modulo handling.
+	(value_replacement): Adjust.
+
 2016-07-15  Virendra Pathak  <virendra.pathak@broadcom.com>
 	    Julian Brown  <julian@codesourcery.com>
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 939fef3af75..b4892fcd515 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-07-15  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/71887
+	* gcc.dg/torture/pr71887.c: New testcase.
+
 2016-07-15  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/71858
diff --git a/gcc/testsuite/gcc.dg/torture/pr71887.c b/gcc/testsuite/gcc.dg/torture/pr71887.c
new file mode 100644
index 00000000000..2df816ae934
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr71887.c
@@ -0,0 +1,11 @@
+/* { dg-do run } */
+
+char a;
+int b;
+
+int main ()
+{
+  unsigned char c = a, d = a;
+  b = d == 0 ? c : c % d;
+  return 0;
+}
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index dd9aa0195fa..dd3837d0da1 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -812,7 +812,7 @@ neutral_element_p (tree_code code, tree arg, bool right)
 /* Returns true if ARG is an absorbing element for operation CODE.  */
 
 static bool
-absorbing_element_p (tree_code code, tree arg, bool right)
+absorbing_element_p (tree_code code, tree arg, bool right, tree rval)
 {
   switch (code)
     {
@@ -827,6 +827,8 @@ absorbing_element_p (tree_code code, tree arg, bool right)
     case RSHIFT_EXPR:
     case LROTATE_EXPR:
     case RROTATE_EXPR:
+      return !right && integer_zerop (arg);
+
     case TRUNC_DIV_EXPR:
     case CEIL_DIV_EXPR:
     case FLOOR_DIV_EXPR:
@@ -836,7 +838,9 @@ absorbing_element_p (tree_code code, tree arg, bool right)
     case CEIL_MOD_EXPR:
     case FLOOR_MOD_EXPR:
     case ROUND_MOD_EXPR:
-      return !right && integer_zerop (arg);
+      return (!right
+	      && integer_zerop (arg)
+	      && tree_single_nonzero_warnv_p (rval, NULL));
 
     default:
       return false;
@@ -1010,9 +1014,10 @@ value_replacement (basic_block cond_bb, basic_block middle_bb,
 	      && neutral_element_p (code_def, cond_rhs, false))
 	  || (operand_equal_for_phi_arg_p (arg1, cond_rhs)
 	      && ((operand_equal_for_phi_arg_p (rhs2, cond_lhs)
-		   && absorbing_element_p (code_def, cond_rhs, true))
+		   && absorbing_element_p (code_def, cond_rhs, true, rhs2))
 		  || (operand_equal_for_phi_arg_p (rhs1, cond_lhs)
-		      && absorbing_element_p (code_def, cond_rhs, false))))))
+		      && absorbing_element_p (code_def,
+					      cond_rhs, false, rhs2))))))
     {
       gsi = gsi_for_stmt (cond);
       if (INTEGRAL_TYPE_P (TREE_TYPE (lhs)))