Hi!
As the following testcase shows, I've missed a check that element type
of lhs type of ovf1/ovf2 (.ADD_OVERFLOW/.SUB_OVERFLOW) matches type (there
are some casts accepted on the way for the case of values in [0-1] range),
so the following testcase got also matched as .SUBC and we get an ICE on
type mismatch in there. The other .{ADD,SUB}_OVERFLOW cases already check
even the result type, both
if (gimple_call_internal_p (ovf, code == PLUS_EXPR
? IFN_ADD_OVERFLOW
: IFN_SUB_OVERFLOW))
...
ovf_lhs = gimple_call_lhs (ovf);
tree ovf_lhs_type = TREE_TYPE (TREE_TYPE (ovf_lhs));
ovf_arg1 = gimple_call_arg (ovf, 0);
ovf_arg2 = gimple_call_arg (ovf, 1);
/* In that case we need to punt if the types don't
mismatch. */
if (!types_compatible_p (type, ovf_lhs_type)
|| !types_compatible_p (type, TREE_TYPE (ovf_arg1))
|| !types_compatible_p (type,
TREE_TYPE (ovf_arg2)))
ovf_lhs = NULL_TREE;
and
gimple *ovf3
= SSA_NAME_DEF_STMT (TREE_OPERAND (gimple_assign_rhs1 (im3), 0));
if (gimple_call_internal_p (ovf3, ifn))
{
lhs = gimple_call_lhs (ovf3);
arg1 = gimple_call_arg (ovf3, 0);
arg2 = gimple_call_arg (ovf3, 1);
if (types_compatible_p (type, TREE_TYPE (TREE_TYPE (lhs)))
&& types_compatible_p (type, TREE_TYPE (arg1))
&& types_compatible_p (type, TREE_TYPE (arg2)))
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2026-02-02 Jakub Jelinek <[email protected]>
PR tree-optimization/121104
* tree-ssa-math-opts.cc (match_uaddc_usubc): Punt if
lhs of ovf1 or ovf2 doesn't have element type compatible with type.
* gcc.dg/pr121104.c: New test.
--- gcc/tree-ssa-math-opts.cc.jj 2026-01-27 10:18:31.525823281 +0100
+++ gcc/tree-ssa-math-opts.cc 2026-01-31 14:00:13.600764201 +0100
@@ -5411,7 +5411,11 @@ match_uaddc_usubc (gimple_stmt_iterator
TYPE_MODE (type)) == CODE_FOR_nothing
|| (rhs[2]
&& optab_handler (code == PLUS_EXPR ? uaddc5_optab : usubc5_optab,
- TYPE_MODE (type)) == CODE_FOR_nothing))
+ TYPE_MODE (type)) == CODE_FOR_nothing)
+ || !types_compatible_p (type,
+ TREE_TYPE (TREE_TYPE (gimple_call_lhs (ovf1))))
+ || !types_compatible_p (type,
+ TREE_TYPE (TREE_TYPE (gimple_call_lhs (ovf2)))))
return false;
tree arg1, arg2, arg3 = NULL_TREE;
gimple *re1 = NULL, *re2 = NULL;
--- gcc/testsuite/gcc.dg/pr121104.c.jj 2026-01-31 14:07:39.051271803 +0100
+++ gcc/testsuite/gcc.dg/pr121104.c 2026-01-31 14:07:27.947458961 +0100
@@ -0,0 +1,23 @@
+/* PR tree-optimization/121104 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+static unsigned long
+foo (unsigned long x, unsigned long y,
+ unsigned long z, unsigned long *w)
+{
+ int r;
+ unsigned long a = __builtin_sub_overflow (x, y, &r);
+ unsigned long b = __builtin_sub_overflow (r, z, &r);
+ *w = a + b;
+ return r;
+}
+
+unsigned long
+bar (unsigned long *p, unsigned long *q)
+{
+ unsigned long c;
+ p[0] = foo (p[0], q[0], 0, &c);
+ p[1] = foo (p[1], q[1], c, &c);
+ return c;
+}
Jakub
