[gcc r14-6601] aarch64: Fix up aarch64_print_operand xzr/wzr case

[Alex Coplan]

https://gcc.gnu.org/g:94415eb7a464e855c37ab01ab300fa5e87e4c4a3

commit r14-6601-g94415eb7a464e855c37ab01ab300fa5e87e4c4a3
Author: Alex Coplan <alex.coplan@arm.com>
Date:   Thu Nov 2 22:53:44 2023 +0000

    aarch64: Fix up aarch64_print_operand xzr/wzr case
    
    This adjusts aarch64_print_operand to recognize zero rtxes in modes other than
    VOIDmode.  This allows us to use xzr/wzr for zero vectors, for example.
    
    We extract the test into a helper function, aarch64_const_zero_rtx_p, since this
    predicate is needed by later patches.
    
    gcc/ChangeLog:
    
            * config/aarch64/aarch64-protos.h (aarch64_const_zero_rtx_p): New.
            * config/aarch64/aarch64.cc (aarch64_const_zero_rtx_p): New.
            Use it ...
            (aarch64_print_operand): ... here.  Recognize CONST0_RTXes in
            modes other than VOIDmode.

Diff:
---
 gcc/config/aarch64/aarch64-protos.h |  1 +
 gcc/config/aarch64/aarch64.cc       | 12 ++++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/gcc/config/aarch64/aarch64-protos.h b/gcc/config/aarch64/aarch64-protos.h
index 88e59426a04..8d6ea73bf3f 100644
--- a/gcc/config/aarch64/aarch64-protos.h
+++ b/gcc/config/aarch64/aarch64-protos.h
@@ -774,6 +774,7 @@ bool aarch64_expand_cpymem (rtx *, bool);
 bool aarch64_expand_setmem (rtx *);
 bool aarch64_float_const_zero_rtx_p (rtx);
 bool aarch64_float_const_rtx_p (rtx);
+bool aarch64_const_zero_rtx_p (rtx);
 bool aarch64_function_arg_regno_p (unsigned);
 bool aarch64_fusion_enabled_p (enum aarch64_fusion_pairs);
 bool aarch64_gen_cpymemqi (rtx *);
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 190608d1381..6d973b3901c 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -10851,6 +10851,15 @@ aarch64_float_const_zero_rtx_p (rtx x)
   return real_equal (CONST_DOUBLE_REAL_VALUE (x), &dconst0);
 }
 
+/* Return true if X is any kind of constant zero rtx.  */
+
+bool
+aarch64_const_zero_rtx_p (rtx x)
+{
+  return (x == CONST0_RTX (GET_MODE (x))
+	  || (CONST_DOUBLE_P (x) && aarch64_float_const_zero_rtx_p (x)));
+}
+
 /* Return TRUE if rtx X is immediate constant that fits in a single
    MOVI immediate operation.  */
 bool
@@ -12054,8 +12063,7 @@ aarch64_print_operand (FILE *f, rtx x, int code)
 
     case 'w':
     case 'x':
-      if (x == const0_rtx
-	  || (CONST_DOUBLE_P (x) && aarch64_float_const_zero_rtx_p (x)))
+      if (aarch64_const_zero_rtx_p (x))
 	{
 	  asm_fprintf (f, "%czr", code);
 	  break;