rs6000: Add PowerPC inline asm redzone clobber support

The following patch on top of the
https://gcc.gnu.org/pipermail/gcc-patches/2024-November/667949.html
patch adds rs6000 part of the support (the only other target I'm aware of
which clearly has red zone as well).

2024-11-28  Jakub Jelinek  <jakub@redhat.com>

	* config/rs6000/rs6000.h (struct machine_function): Add
	asm_redzone_clobber_seen member.
	* config/rs6000/rs6000-logue.cc (rs6000_stack_info): Force
	info->push_p if cfun->machine->asm_redzone_clobber_seen.
	* config/rs6000/rs6000.cc (TARGET_REDZONE_CLOBBER): Redefine.
	(rs6000_redzone_clobber): New function.

	* gcc.target/powerpc/asm-redzone-1.c: New test.

4 files changed, 94 insertions, 1 deletions

diff --git a/gcc/config/rs6000/rs6000-logue.cc b/gcc/config/rs6000/rs6000-logue.cc
index c87058b..2efb8b1 100644
--- a/gcc/config/rs6000/rs6000-logue.cc
+++ b/gcc/config/rs6000/rs6000-logue.cc
@@ -918,7 +918,7 @@ rs6000_stack_info (void)
   else if (DEFAULT_ABI == ABI_V4)
     info->push_p = non_fixed_size != 0;
 
-  else if (frame_pointer_needed)
+  else if (frame_pointer_needed || cfun->machine->asm_redzone_clobber_seen)
     info->push_p = 1;
 
   else
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 3c25315..02a2f11 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -1751,6 +1751,9 @@ static const scoped_attribute_specs *const rs6000_attribute_table[] =
 #undef TARGET_CAN_CHANGE_MODE_CLASS
 #define TARGET_CAN_CHANGE_MODE_CLASS rs6000_can_change_mode_class
 
+#undef TARGET_REDZONE_CLOBBER
+#define TARGET_REDZONE_CLOBBER rs6000_redzone_clobber
+
 #undef TARGET_CONSTANT_ALIGNMENT
 #define TARGET_CONSTANT_ALIGNMENT rs6000_constant_alignment
 
@@ -13725,6 +13728,24 @@ rs6000_can_change_mode_class (machine_mode from,
   return true;
 }
 
+/* Implement TARGET_REDZONE_CLOBBER.  */
+
+static rtx
+rs6000_redzone_clobber ()
+{
+  cfun->machine->asm_redzone_clobber_seen = true;
+  if (DEFAULT_ABI != ABI_V4)
+    {
+      int red_zone_size = TARGET_32BIT ? 220 : 288;
+      rtx base = plus_constant (Pmode, stack_pointer_rtx,
+				GEN_INT (-red_zone_size));
+      rtx mem = gen_rtx_MEM (BLKmode, base);
+      set_mem_size (mem, red_zone_size);
+      return mem;
+    }
+  return NULL_RTX;
+}
+
 /* Debug version of rs6000_can_change_mode_class.  */
 static bool
 rs6000_debug_can_change_mode_class (machine_mode from,
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index e0c41e1..926b6b2 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -2421,6 +2421,7 @@ typedef struct GTY(()) machine_function
      global entry.  It helps to control the patchable area before and after
      local entry.  */
   bool global_entry_emitted;
+  bool asm_redzone_clobber_seen;
 } machine_function;
 #endif
 
diff --git a/gcc/testsuite/gcc.target/powerpc/asm-redzone-1.c b/gcc/testsuite/gcc.target/powerpc/asm-redzone-1.c
new file mode 100644
index 0000000..87b9180
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/asm-redzone-1.c
@@ -0,0 +1,71 @@
+/* { dg-do run { target lp64 } } */
+/* { dg-options "-O2" } */
+
+__attribute__((noipa)) int
+foo (void)
+{
+  int a = 1;
+  int b = 2;
+  int c = 3;
+  int d = 4;
+  int e = 5;
+  int f = 6;
+  int g = 7;
+  int h = 8;
+  int i = 9;
+  int j = 10;
+  int k = 11;
+  int l = 12;
+  int m = 13;
+  int n = 14;
+  int o = 15;
+  int p = 16;
+  int q = 17;
+  int r = 18;
+  int s = 19;
+  int t = 20;
+  int u = 21;
+  int v = 22;
+  int w = 23;
+  int x = 24;
+  int y = 25;
+  int z = 26;
+  asm volatile ("" : "+g" (a), "+g" (b), "+g" (c), "+g" (d), "+g" (e));
+  asm volatile ("" : "+g" (f), "+g" (g), "+g" (h), "+g" (i), "+g" (j));
+  asm volatile ("" : "+g" (k), "+g" (l), "+g" (m), "+g" (n), "+g" (o));
+  asm volatile ("" : "+g" (k), "+g" (l), "+g" (m), "+g" (n), "+g" (o));
+  asm volatile ("" : "+g" (p), "+g" (q), "+g" (s), "+g" (t), "+g" (u));
+  asm volatile ("" : "+g" (v), "+g" (w), "+g" (y), "+g" (z));
+#ifdef __PPC64__
+  asm volatile ("std 1,-8(1); std 1,-16(1); std 1,-24(1); std 1,-32(1)"
+		: : : "18", "19", "20", "redzone");
+#elif defined(_AIX)
+  asm volatile ("stw 1,-4(1); stw 1,-8(1); stw 1,-12(1); stw 1,-16(1)"
+		: : : "18", "19", "20", "redzone");
+#endif
+  asm volatile ("" : "+g" (a), "+g" (b), "+g" (c), "+g" (d), "+g" (e));
+  asm volatile ("" : "+g" (f), "+g" (g), "+g" (h), "+g" (i), "+g" (j));
+  asm volatile ("" : "+g" (k), "+g" (l), "+g" (m), "+g" (n), "+g" (o));
+  asm volatile ("" : "+g" (p), "+g" (q), "+g" (s), "+g" (t), "+g" (u));
+  asm volatile ("" : "+g" (v), "+g" (w), "+g" (y), "+g" (z));
+  return a + b + c + d + e + f + g + h + i + j + k + l + m + n;
+}
+
+__attribute__((noipa)) void
+bar (char *p, long *q)
+{
+  (void) p;
+  *q = 42;
+}
+
+int
+main ()
+{
+  volatile int x = 256;
+  long y;
+  bar (__builtin_alloca (x), &y);
+  if (foo () != 105)
+    __builtin_abort ();
+  if (y != 42)
+    __builtin_abort ();
+}