From: Richard Biener <rguenther@suse.de>
Date: Wed, 10 Apr 2024 08:33:40 +0000 (+0200)
Subject: tree-optimization/114672 - WIDEN_MULT_PLUS_EXPR type mismatch
X-Git-Tag: basepoints/gcc-15~247
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=912753cc5f18d786e334dd425469fa7f93155661;p=thirdparty%2Fgcc.git

tree-optimization/114672 - WIDEN_MULT_PLUS_EXPR type mismatch

The following makes sure to restrict WIDEN_MULT*_EXPR to a mode
precision final compute type as the mode is used to find the optab
and type checking chokes when seeing bit-precisions later which
would likely also not properly expanded to RTL.

	PR tree-optimization/114672
	* tree-ssa-math-opts.cc (convert_plusminus_to_widen): Only
	allow mode-precision results.

	* gcc.dg/torture/pr114672.c: New testcase.
---

diff --git a/gcc/testsuite/gcc.dg/torture/pr114672.c b/gcc/testsuite/gcc.dg/torture/pr114672.c
new file mode 100644
index 000000000000..b69511fe8db9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr114672.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+
+struct {
+  __INT64_TYPE__ m : 60;
+} s;
+
+short a;
+short b;
+
+void
+foo ()
+{
+  s.m += a * b;
+}
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index a8d25c2de48a..705f4a4695ac 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -2918,8 +2918,9 @@ convert_plusminus_to_widen (gimple_stmt_iterator *gsi, gimple *stmt,
 
   lhs = gimple_assign_lhs (stmt);
   type = TREE_TYPE (lhs);
-  if (TREE_CODE (type) != INTEGER_TYPE
-      && TREE_CODE (type) != FIXED_POINT_TYPE)
+  if ((TREE_CODE (type) != INTEGER_TYPE
+       && TREE_CODE (type) != FIXED_POINT_TYPE)
+      || !type_has_mode_precision_p (type))
     return false;
 
   if (code == MINUS_EXPR)