[committed][PR rtl-optimization/122575] Fix mode on optimized IOR comparison

[Jeff Law]

As Andrew P recognized, we were using the wrong mode when simplifying 
certain equality tests like (eq (ior (ne x 0 (y)).  Sam took Andrew's 
suggestion and verified it fixed the problem he was stumbling over.

So even though I haven't recreated the problem, I'm reasonably confident 
we've got the right fix.  I've bootstrapped and regression tested on x86.

Pushing to the trunk.

jeff

commit 2e1d74b27283b5c20b0e1611c358dbf4e62db54f
Author: Jeff Law <j...@ventanamicro.com>
Date:   Mon Nov 17 10:40:46 2025 -0700

    [PR rtl-optimization/122575] Fix mode on optimized IOR comparison
    
    As Andrew P recognized, we were using the wrong mode when simplifying 
certain
    equality tests like (eq (ior (ne x 0 (y)).  Sam took Andrew's suggestion and
    verified it fixed the problem he was stumbling over.
    
    So even though I haven't recreated the problem, I'm reasonably confident 
we've
    got the right fix.  I've bootstrapped and regression tested on x86.
    
            PR rtl-optimization/122575
    gcc/
            * simplify-rtx.cc 
(simplify_context::simplify_relational_operation_1):
            Use correct mode for simplified IOR expression inside equality
            conditional.

diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 2f7ad2de1d19..86baeb06ad48 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -6500,10 +6500,10 @@ simplify_context::simplify_relational_operation_1 
(rtx_code code,
          /* only enters if op1 is 0 */
          /* Verify IOR operand is NE */
          && GET_CODE (XEXP (op0, 0)) == NE
-         /* Verfiy second NE operand is 0 */
+         /* Verify second NE operand is 0 */
          && XEXP (XEXP (op0, 0), 1) == CONST0_RTX (mode))
        {
-         rtx t = gen_rtx_IOR (mode, XEXP (XEXP (op0, 0), 0), XEXP (op0, 1));
+         rtx t = gen_rtx_IOR (cmp_mode, XEXP (XEXP (op0, 0), 0), XEXP (op0, 
1));
          t = gen_rtx_fmt_ee (code, mode, t, CONST0_RTX (mode));
          return t;
        }