From: Richard Biener <rguenther@suse.de>
Date: Fri, 29 Nov 2019 08:05:03 +0000 (+0000)
Subject: re PR tree-optimization/92704 (ICE: Segmentation fault (in process_bb))
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d5e82c9f686f6c8e2feabfe753258f9fc13d980f;p=gcc.git

re PR tree-optimization/92704 (ICE: Segmentation fault (in process_bb))

2019-11-29  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/92704
	* tree-if-conv.c (combine_blocks): Deal with virtual PHIs
	in loops performing only loads.

	* gcc.dg/torture/pr92704.c: New testcase.

From-SVN: r278828
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b89f404a8b8..1ef3bc2de74 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-11-29  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/92704
+	* tree-if-conv.c (combine_blocks): Deal with virtual PHIs
+	in loops performing only loads.
+
 2019-11-29  Julian Brown  <julian@codesourcery.com>
 
 	* builtin-types.def (BT_DFLOAT32_PTR, BT_DFLOAT64_PTR,
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f5bb0d2113e..b787896dd57 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-11-29  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/92704
+	* gcc.dg/torture/pr92704.c: New testcase.
+
 2019-11-29  Joseph Myers  <joseph@codesourcery.com>
 
 	* objc.dg/attributes/gnu2x-attr-syntax-1.m: New test.
diff --git a/gcc/testsuite/gcc.dg/torture/pr92704.c b/gcc/testsuite/gcc.dg/torture/pr92704.c
new file mode 100644
index 00000000000..79994a39b54
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr92704.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-fexceptions -fnon-call-exceptions -fno-tree-dce -ftree-loop-if-convert" } */
+int zr, yx;
+
+void __attribute__ ((simd))
+oj (int rd, int q7)
+{
+  int wo = (__UINTPTR_TYPE__)&rd;
+
+  while (q7 < 1)
+    {
+      int kv;
+      short int v3;
+
+      for (v3 = 0; v3 < 82; v3 += 3)
+        {
+        }
+
+      kv = zr ? 0 : v3;
+      yx = kv < rd;
+      zr = zr && yx;
+      ++q7;
+    }
+}
diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c
index 33d6cddb460..d2e40d43373 100644
--- a/gcc/tree-if-conv.c
+++ b/gcc/tree-if-conv.c
@@ -2624,6 +2624,11 @@ combine_blocks (class loop *loop)
       vphi = get_virtual_phi (bb);
       if (vphi)
 	{
+	  /* When there's just loads inside the loop a stray virtual
+	     PHI merging the uses can appear, update last_vdef from
+	     it.  */
+	  if (!last_vdef)
+	    last_vdef = gimple_phi_arg_def (vphi, 0);
 	  imm_use_iterator iter;
 	  use_operand_p use_p;
 	  gimple *use_stmt;
@@ -2655,6 +2660,10 @@ combine_blocks (class loop *loop)
 	      if (gimple_vdef (stmt))
 		last_vdef = gimple_vdef (stmt);
 	    }
+	  else
+	    /* If this is the first load we arrive at update last_vdef
+	       so we handle stray PHIs correctly.  */
+	    last_vdef = gimple_vuse (stmt);
 	  if (predicated[i])
 	    {
 	      ssa_op_iter i;