[PATCH v2 06/11] aarch64: Fix up aarch64_print_operand xzr/wzr case

[Alex Coplan]

Hi,

This is a v2 of:

https://gcc.gnu.org/pipermail/gcc-patches/2023-November/637612.html

v1 was approved as-is, but this version pulls out the test into a helper
function which is used by later patches in the series.

Bootstrapped/regtested as a series on aarch64-linux-gnu, OK for trunk?

Thanks,
Alex

-- >8 --

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 --git a/gcc/config/aarch64/aarch64-protos.h 
b/gcc/config/aarch64/aarch64-protos.h
index d2718cc87b3..27fc6ccf098 100644
--- a/gcc/config/aarch64/aarch64-protos.h
+++ b/gcc/config/aarch64/aarch64-protos.h
@@ -773,6 +773,7 @@ bool aarch64_expand_cpymem (rtx *);
 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 fca64daf2a0..a35c6bbe335 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -9095,6 +9095,15 @@ 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
@@ -9977,8 +9986,7 @@ 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;