From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 26 Apr 2022 07:57:34 +0000 (+0200)
Subject: reassoc: Don't call fold_convert if !fold_convertible_p [PR105374]
X-Git-Tag: basepoints/gcc-13~50
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d4836ac9acd0c991a4fe1dec9438773a2c4eb5ac;p=thirdparty%2Fgcc.git

reassoc: Don't call fold_convert if !fold_convertible_p [PR105374]

As mentioned in the PR, we ICE because maybe_fold_*_comparisons returns
an expression with V4SImode type and we try to fold_convert it to
V4BImode, which isn't allowed.

IMHO no matter whether we change maybe_fold_*_comparisons we should
play safe on the reassoc side and punt if we can't convert like
we punt for many other reasons.  This fixes the testcase on ARM.

Testcase not included, not exactly sure where and what directives it
should have in gcc.target/arm/ testsuite.  Christophe, do you think you
could handle that incrementally?

2022-04-26  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/105374
	* tree-ssa-reassoc.cc (eliminate_redundant_comparison): Punt if
	!fold_convertible_p rather than assuming fold_convert must succeed.
---

diff --git a/gcc/tree-ssa-reassoc.cc b/gcc/tree-ssa-reassoc.cc
index f41b3c9a004c..43b25371d4b0 100644
--- a/gcc/tree-ssa-reassoc.cc
+++ b/gcc/tree-ssa-reassoc.cc
@@ -2254,7 +2254,11 @@ eliminate_redundant_comparison (enum tree_code opcode,
 	 BIT_AND_EXPR or BIT_IOR_EXPR was of a wider integer type,
 	 we need to convert.  */
       if (!useless_type_conversion_p (TREE_TYPE (curr->op), TREE_TYPE (t)))
-	t = fold_convert (TREE_TYPE (curr->op), t);
+	{
+	  if (!fold_convertible_p (TREE_TYPE (curr->op), t))
+	    continue;
+	  t = fold_convert (TREE_TYPE (curr->op), t);
+	}
 
       if (TREE_CODE (t) != INTEGER_CST
 	  && !operand_equal_p (t, curr->op, 0))