[gcc r12-9461] Fix handling of large arguments passed by value.

[gcc r12-9461] Fix handling of large arguments passed by value.

[John David Anglin]

https://gcc.gnu.org/g:dca9419cc3844d3cf3c06f51d5ca57e3b5f50920

commit r12-9461-gdca9419cc3844d3cf3c06f51d5ca57e3b5f50920
Author: John David Anglin <danglin@gcc.gnu.org>
Date:   Fri Apr 21 14:38:42 2023 +0000

    Fix handling of large arguments passed by value.
    
    2023-04-15  John David Anglin  <danglin@gcc.gnu.org>
    
    gcc/ChangeLog:
    
            PR target/109478
            * config/pa/pa-protos.h (pa_function_arg_size): Update prototype.
            * config/pa/pa.cc (pa_function_arg): Return NULL_RTX if argument
            size is zero.
            (pa_arg_partial_bytes): Don't call pa_function_arg_size twice.
            (pa_function_arg_size): Change return type to int.  Return zero
            for arguments larger than 1 GB.  Update comments.

Diff:
---
 gcc/config/pa/pa-protos.h |  2 +-
 gcc/config/pa/pa.cc       | 27 +++++++++++++++++++--------
 2 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/gcc/config/pa/pa-protos.h b/gcc/config/pa/pa-protos.h
index fe8b7a5091e..6b587538e94 100644
--- a/gcc/config/pa/pa-protos.h
+++ b/gcc/config/pa/pa-protos.h
@@ -106,7 +106,7 @@ extern void pa_asm_output_aligned_local (FILE *, const char *,
 					 unsigned int);
 extern void pa_hpux_asm_output_external (FILE *, tree, const char *);
 extern HOST_WIDE_INT pa_initial_elimination_offset (int, int);
-extern HOST_WIDE_INT pa_function_arg_size (machine_mode, const_tree);
+extern int pa_function_arg_size (machine_mode, const_tree);
 extern void pa_output_function_label (FILE *);
 extern void hppa_profile_hook (int);
 
diff --git a/gcc/config/pa/pa.cc b/gcc/config/pa/pa.cc
index 9f43802075f..65f8fe814c6 100644
--- a/gcc/config/pa/pa.cc
+++ b/gcc/config/pa/pa.cc
@@ -9784,6 +9784,8 @@ pa_function_arg (cumulative_args_t cum_v, const function_arg_info &arg)
     return NULL_RTX;
 
   arg_size = pa_function_arg_size (mode, type);
+  if (!arg_size)
+    return NULL_RTX;
 
   /* If this arg would be passed partially or totally on the stack, then
      this routine should return zero.  pa_arg_partial_bytes will
@@ -9985,15 +9987,16 @@ pa_arg_partial_bytes (cumulative_args_t cum_v, const function_arg_info &arg)
   CUMULATIVE_ARGS *cum = get_cumulative_args (cum_v);
   unsigned int max_arg_words = 8;
   unsigned int offset = 0;
+  int arg_size;
 
   if (!TARGET_64BIT)
     return 0;
 
-  if (pa_function_arg_size (arg.mode, arg.type) > 1 && (cum->words & 1))
+  arg_size = pa_function_arg_size (arg.mode, arg.type);
+  if (arg_size > 1 && (cum->words & 1))
     offset = 1;
 
-  if (cum->words + offset + pa_function_arg_size (arg.mode, arg.type)
-      <= max_arg_words)
+  if (cum->words + offset + arg_size <= max_arg_words)
     /* Arg fits fully into registers.  */
     return 0;
   else if (cum->words + offset >= max_arg_words)
@@ -11067,17 +11070,25 @@ pa_starting_frame_offset (void)
   return 8;
 }
 
-/* Figure out the size in words of the function argument.  The size
-   returned by this function should always be greater than zero because
-   we pass variable and zero sized objects by reference.  */
+/* Figure out the size in words of the function argument.  */
 
-HOST_WIDE_INT
+int
 pa_function_arg_size (machine_mode mode, const_tree type)
 {
   HOST_WIDE_INT size;
 
   size = mode != BLKmode ? GET_MODE_SIZE (mode) : int_size_in_bytes (type); 
-  return CEIL (size, UNITS_PER_WORD);
+
+  /* The 64-bit runtime does not restrict the size of stack frames,
+     but the gcc calling conventions limit argument sizes to 1G.  Our
+     prologue/epilogue code limits frame sizes to just under 32 bits.
+     1G is also the maximum frame size that can be handled by the HPUX
+     unwind descriptor.  Since very large TYPE_SIZE_UNIT values can
+     occur for (parallel:BLK []), we need to ignore large arguments
+     passed by value.  */
+  if (size >= (1 << (HOST_BITS_PER_INT - 2)))
+    size = 0;
+  return (int) CEIL (size, UNITS_PER_WORD);
 }
 
 #include "gt-pa.h"