[gcc r14-8194] aarch64: Fix aarch64_ldp_reg_operand predicate not to allow all subreg [PR113221]

[gcc r14-8194] aarch64: Fix aarch64_ldp_reg_operand predicate not to allow all subreg [PR113221]

[Andrew Pinski]

https://gcc.gnu.org/g:7a8124e341aebcc544b4720e920b625f4ffe4e8a

commit r14-8194-g7a8124e341aebcc544b4720e920b625f4ffe4e8a
Author: Andrew Pinski <quic_apinski@quicinc.com>
Date:   Tue Jan 16 15:37:49 2024 -0800

    aarch64: Fix aarch64_ldp_reg_operand predicate not to allow all subreg [PR113221]
    
    So the problem here is that aarch64_ldp_reg_operand will all subreg even subreg of lo_sum.
    When LRA tries to fix that up, all things break. So the fix is to change the check to only
    allow reg and subreg of regs.
    
    Note the tendancy here is to use register_operand but that checks the mode of the register
    but we need to allow a mismatch modes for this predicate for now.
    
    Built and tested for aarch64-linux-gnu with no regressions
    (Also tested with the LD/ST pair pass back on).
    
            PR target/113221
    
    gcc/ChangeLog:
    
            * config/aarch64/predicates.md (aarch64_ldp_reg_operand): For subreg,
            only allow REG operands instead of allowing all.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.c-torture/compile/pr113221-1.c: New test.
    
    Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>

Diff:
---
 gcc/config/aarch64/predicates.md                 |  6 +++++-
 gcc/testsuite/gcc.c-torture/compile/pr113221-1.c | 12 ++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/gcc/config/aarch64/predicates.md b/gcc/config/aarch64/predicates.md
index 8a204e48bb5..b895f5dcb86 100644
--- a/gcc/config/aarch64/predicates.md
+++ b/gcc/config/aarch64/predicates.md
@@ -313,7 +313,11 @@
 
 (define_special_predicate "aarch64_ldp_reg_operand"
   (and
-    (match_code "reg,subreg")
+    (ior
+      (match_code "reg")
+      (and
+       (match_code "subreg")
+       (match_test "REG_P (SUBREG_REG (op))")))
     (match_test "aarch64_ldpstp_operand_mode_p (GET_MODE (op))")
     (ior
       (match_test "mode == VOIDmode")
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr113221-1.c b/gcc/testsuite/gcc.c-torture/compile/pr113221-1.c
new file mode 100644
index 00000000000..942fa5eea88
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr113221-1.c
@@ -0,0 +1,12 @@
+/* { dg-options "-fno-move-loop-invariants -funroll-all-loops" } */
+/* PR target/113221 */
+/* This used to ICE after the `load/store pair fusion pass` was added
+   due to the predicate aarch64_ldp_reg_operand allowing too much. */
+
+
+void bar();
+void foo(int* b) {
+  for (;;)
+    *b++ = (__SIZE_TYPE__)bar;
+}
+