On Tue, 21 Jun 2022, Jakub Jelinek wrote:
> Hi!
>
> If expand_cond_expr_using_cmove can't find a cmove optab for a particular
> mode, it tries to promote the mode and perform the cmove in the promoted
> mode.
>
> The testcase in the patch ICEs on arm because in that case we pass temp which
> has the promoted mode (SImode) as target to expand_operands where the
> operands have the non-promoted mode (QImode).
> Later on the function uses paradoxical subregs:
> if (GET_MODE (op1) != mode)
> op1 = gen_lowpart (mode, op1);
>
> if (GET_MODE (op2) != mode)
> op2 = gen_lowpart (mode, op2);
> to change the operand modes.
>
> The following patch fixes it by passing NULL_RTX as target if it has
> promoted mode.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux and tested with cross
> to arm on the testcase, ok for trunk?
OK.
Thanks,
Richard.
> 2022-06-21 Jakub Jelinek <ja...@redhat.com>
>
> PR middle-end/106030
> * expr.cc (expand_cond_expr_using_cmove): Pass NULL_RTX instead of
> temp to expand_operands if mode has been promoted.
>
> * gcc.c-torture/compile/pr106030.c: New test.
>
> --- gcc/expr.cc.jj 2022-06-10 21:19:12.087803729 +0200
> +++ gcc/expr.cc 2022-06-20 14:10:07.941681072 +0200
> @@ -8832,7 +8832,8 @@ expand_cond_expr_using_cmove (tree treeo
> expanding_cond_expr_using_cmove = true;
> start_sequence ();
> expand_operands (treeop1, treeop2,
> - temp, &op1, &op2, EXPAND_NORMAL);
> + mode == orig_mode ? temp : NULL_RTX, &op1, &op2,
> + EXPAND_NORMAL);
>
> if (TREE_CODE (treeop0) == SSA_NAME
> && (srcstmt = get_def_for_expr_class (treeop0, tcc_comparison)))
> --- gcc/testsuite/gcc.c-torture/compile/pr106030.c.jj 2022-06-20
> 14:49:37.618142233 +0200
> +++ gcc/testsuite/gcc.c-torture/compile/pr106030.c 2022-06-20
> 14:49:19.016382117 +0200
> @@ -0,0 +1,16 @@
> +/* PR middle-end/106030 */
> +
> +int a, b, c;
> +
> +char
> +foo (int x, int y)
> +{
> + return x * y;
> +}
> +
> +void
> +bar (void)
> +{
> + char d = (foo <= b) * a;
> + c = foo (2 != bar, d);
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstraße 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)
