[gcc r13-4975] expr: Fix up store_expr into SUBREG_PROMOTED_* target [PR108264]

[gcc r13-4975] expr: Fix up store_expr into SUBREG_PROMOTED_* target [PR108264]

[Jakub Jelinek]

https://gcc.gnu.org/g:226a498733e7919de72eb6f1bf3e16883ad159f6

commit r13-4975-g226a498733e7919de72eb6f1bf3e16883ad159f6
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Jan 3 12:13:24 2023 +0100

    expr: Fix up store_expr into SUBREG_PROMOTED_* target [PR108264]
    
    The following testcase ICEs on s390x-linux (e.g. with -march=z13).
    The problem is that target is (subreg/s/u:SI (reg/v:DI 66 [ x+-4 ]) 4)
    and we call convert_move from temp to the SUBREG_REG of that, expecting
    to extend the value properly.  That works nicely if temp has some
    scalar integer mode (or partial one), but ICEs when temp has V4QImode
    on the assertion that from and to modes have the same bitsize.
    store_expr generally allows say store from V4QI to SI target because
    they have the same size and if temp is a CONST_INT, we already have code
    to convert the constant properly, so the following patch just adds handling
    of non-scalar integer modes by converting them to the mode of target
    first before convert_move extends them.
    
    2023-01-03  Jakub Jelinek  <jakub@redhat.com>
    
            PR middle-end/108264
            * expr.cc (store_expr): For stores into SUBREG_PROMOTED_* targets
            from source which doesn't have scalar integral mode first convert
            it to outer_mode.
    
            * gcc.dg/pr108264.c: New test.

Diff:
---
 gcc/expr.cc                     |  3 +++
 gcc/testsuite/gcc.dg/pr108264.c | 27 +++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/gcc/expr.cc b/gcc/expr.cc
index 372ad3439a8..15be1c8db99 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -6226,6 +6226,9 @@ store_expr (tree exp, rtx target, int call_param_p,
 	  temp = convert_modes (inner_mode, outer_mode, temp,
 				SUBREG_PROMOTED_SIGN (target));
 	}
+      else if (!SCALAR_INT_MODE_P (GET_MODE (temp)))
+	temp = convert_modes (outer_mode, TYPE_MODE (TREE_TYPE (exp)),
+			      temp, SUBREG_PROMOTED_SIGN (target));
 
       convert_move (SUBREG_REG (target), temp,
 		    SUBREG_PROMOTED_SIGN (target));
diff --git a/gcc/testsuite/gcc.dg/pr108264.c b/gcc/testsuite/gcc.dg/pr108264.c
new file mode 100644
index 00000000000..ff9aa261d67
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr108264.c
@@ -0,0 +1,27 @@
+/* PR middle-end/108264 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-additional-options "-fpic" { target fpic } } */
+
+int v;
+extern int bar (void);
+
+static inline void
+foo (char *d)
+{
+  switch (bar ())
+    {
+    case 2:
+      d[0] = d[1] = d[2] = d[3] = v;
+      break;
+    case 4:
+      d[0] = 0;
+    }
+}
+
+int
+baz (int x)
+{
+  foo ((char *) &x);
+  return x;
+}