[gcc r13-10494] AVR: Provide pushti1 to fix passing vector(16) in memory

[Georg-Johann Lay]

https://gcc.gnu.org/g:fcb1fb684f2939b68360133d11a7caa84df4272b

commit r13-10494-gfcb1fb684f2939b68360133d11a7caa84df4272b
Author: Georg-Johann Lay <avr@gjlay.de>
Date:   Sat Aug 29 13:25:49 2026 +0200

    AVR: Provide pushti1 to fix passing vector(16) in memory
    
    This patch adds TImode to the MPUSH mode iterator that
    determines which push<mode>1 insns are available.
    It fixes passing vector(16) in memory.
    
    Push insns work around expr.cc which doesn't work properly for
    STACK_GROWS_DOWNWARDS + POST_DEC push.
    
            PR middle-end/127098
    gcc/
            * config/avr/avr.md (MPUSH): Add TImode to mode iterator.
            * config/avr/avr.h (PUSH_ROUNDING): Adjust comment.
    gcc/testsuite/
            * gcc.target/avr/torture/pr127098.c: New test.
    
    (cherry picked from commit 96a3184a784fe96c19ca9b15866162a01045b9de)

Diff:
---
 gcc/config/avr/avr.h                            | 10 +++++-----
 gcc/config/avr/avr.md                           |  2 +-
 gcc/testsuite/gcc.target/avr/torture/pr127098.c | 21 +++++++++++++++++++++
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/gcc/config/avr/avr.h b/gcc/config/avr/avr.h
index 9939ab6ee77c..e9b65a8c81c6 100644
--- a/gcc/config/avr/avr.h
+++ b/gcc/config/avr/avr.h
@@ -322,10 +322,6 @@ enum reg_class {
 
 #define RETURN_ADDR_RTX(count, tem) avr_return_addr_rtx (count, tem)
 
-/* Don't use Push rounding. expr.cc: emit_single_push_insn is broken 
-   for POST_DEC targets (PR27386).  */
-/*#define PUSH_ROUNDING(NPUSHED) (NPUSHED)*/
-
 typedef struct avr_args
 {
   /* # Registers available for passing */
@@ -595,7 +591,11 @@ struct GTY(()) machine_function
 };
 
 /* AVR does not round pushes, but the existence of this macro is
-   required in order for pushes to be generated.  */
+   required in order for pushes to be generated.
+   This macro was removed for PR27386 and then later re-added when
+   push insns were introduced.  Push insns can work around broken
+   argument setup in expr.cc that doesn't work properly for
+   STACK_GROWS_DOWNWARDS + POST_DEC push, see PR127098.  */
 #define PUSH_ROUNDING(X)	(X)
 
 /* Define prototype here to avoid build warning.  Some files using
diff --git a/gcc/config/avr/avr.md b/gcc/config/avr/avr.md
index c071effcb048..ed37b634818d 100644
--- a/gcc/config/avr/avr.md
+++ b/gcc/config/avr/avr.md
@@ -425,7 +425,7 @@
    HI CHI HA UHA HQ UHQ
    SI CSI SA USA SQ USQ
    DI CDI DA UDA DQ UDQ
-   TA UTA
+   TA UTA TI
    SF DF SC DC
    PSI])
 
diff --git a/gcc/testsuite/gcc.target/avr/torture/pr127098.c b/gcc/testsuite/gcc.target/avr/torture/pr127098.c
new file mode 100644
index 000000000000..c3931f9e3ff1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/avr/torture/pr127098.c
@@ -0,0 +1,21 @@
+/* { dg-do run } */
+
+#define NI __attribute((noipa))
+
+typedef char U __attribute__ ((vector_size (16)));
+
+NI void fun (long i, U u)
+{
+  (void) i;
+  if (u[0] != 1)
+    __builtin_abort ();
+}
+
+U u = { 1 };
+
+int main (void)
+{
+  fun (0, u);
+
+  return 0;
+}