[gcc r12-10410] tree-optimization/114672 - WIDEN_MULT_PLUS_EXPR type mismatch

[Richard Ball <ricbal02@gcc.gnu.org>]

https://gcc.gnu.org/g:87e37c72cfb153d65ac8b26d6f2d1fe155818318

commit r12-10410-g87e37c72cfb153d65ac8b26d6f2d1fe155818318
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Apr 10 10:33:40 2024 +0200

    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.
    
    (cherry picked from commit 912753cc5f18d786e334dd425469fa7f93155661)

Diff:
---
 gcc/testsuite/gcc.dg/torture/pr114672.c | 14 ++++++++++++++
 gcc/tree-ssa-math-opts.cc               |  5 +++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/torture/pr114672.c b/gcc/testsuite/gcc.dg/torture/pr114672.c
new file mode 100644
index 00000000000..b69511fe8db
--- /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 bab0cc5aef4..ffd8eebd2a9 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -2802,8 +2802,9 @@ 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)