[gcc r13-1185] expand: Fix up expand_cond_expr_using_cmove [PR106030]

[gcc r13-1185] expand: Fix up expand_cond_expr_using_cmove [PR106030]

[Jakub Jelinek]

https://gcc.gnu.org/g:2df1df945fac85d7b3d084001414a66a2709d8fe

commit r13-1185-g2df1df945fac85d7b3d084001414a66a2709d8fe
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Jun 21 11:38:59 2022 +0200

    expand: Fix up expand_cond_expr_using_cmove [PR106030]
    
    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.
    
    2022-06-21  Jakub Jelinek  <jakub@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.

Diff:
---
 gcc/expr.cc                                    |  3 ++-
 gcc/testsuite/gcc.c-torture/compile/pr106030.c | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/gcc/expr.cc b/gcc/expr.cc
index 78c839ab425..c90cde35006 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -8832,7 +8832,8 @@ expand_cond_expr_using_cmove (tree treeop0 ATTRIBUTE_UNUSED,
   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)))
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr106030.c b/gcc/testsuite/gcc.c-torture/compile/pr106030.c
new file mode 100644
index 00000000000..7514b348ff9
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr106030.c
@@ -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);
+}