Previous patches ensured that the final frame allocation only needs
a probe when the size is strictly greater than 1KiB.  It's therefore
safe to use the normal 1024 probe offset in all cases.

The main motivation for doing this is to simplify the code and
remove the number of special cases.

gcc/
        * config/aarch64/aarch64.cc (aarch64_allocate_and_probe_stack_space):
        Always probe the residual allocation at offset 1024, asserting
        that that is in range.

gcc/testsuite/
        * gcc.target/aarch64/stack-check-prologue-17.c: Expect the probe
        to be at offset 1024 rather than offset 0.
        * gcc.target/aarch64/stack-check-prologue-18.c: Likewise.
        * gcc.target/aarch64/stack-check-prologue-19.c: Likewise.
---
 gcc/config/aarch64/aarch64.cc                        | 12 ++++--------
 .../gcc.target/aarch64/stack-check-prologue-17.c     |  2 +-
 .../gcc.target/aarch64/stack-check-prologue-18.c     |  4 ++--
 .../gcc.target/aarch64/stack-check-prologue-19.c     |  4 ++--
 4 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 383b32f2078..bcb879ba94b 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -9887,16 +9887,12 @@ aarch64_allocate_and_probe_stack_space (rtx temp1, rtx 
temp2,
      are still safe.  */
   if (residual)
     {
-      HOST_WIDE_INT residual_probe_offset = guard_used_by_caller;
+      gcc_assert (guard_used_by_caller + byte_sp_alignment <= size);
+
       /* If we're doing final adjustments, and we've done any full page
         allocations then any residual needs to be probed.  */
       if (final_adjustment_p && rounded_size != 0)
        min_probe_threshold = 0;
-      /* If doing a small final adjustment, we always probe at offset 0.
-        This is done to avoid issues when the final adjustment is smaller
-        than the probing offset.  */
-      else if (final_adjustment_p && rounded_size == 0)
-       residual_probe_offset = 0;
 
       aarch64_sub_sp (temp1, temp2, residual, frame_related_p);
       if (residual >= min_probe_threshold)
@@ -9907,8 +9903,8 @@ aarch64_allocate_and_probe_stack_space (rtx temp1, rtx 
temp2,
                     HOST_WIDE_INT_PRINT_DEC " bytes, probing will be required."
                     "\n", residual);
 
-           emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
-                                            residual_probe_offset));
+         emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
+                                          guard_used_by_caller));
          emit_insn (gen_blockage ());
        }
     }
diff --git a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-17.c 
b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-17.c
index 0d8a25d73a2..f0ec1389771 100644
--- a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-17.c
+++ b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-17.c
@@ -33,7 +33,7 @@ int test1(int z) {
 **     ...
 **     str     x30, \[sp\]
 **     sub     sp, sp, #1040
-**     str     xzr, \[sp\]
+**     str     xzr, \[sp, #?1024\]
 **     cbnz    w0, .*
 **     bl      g
 **     ...
diff --git a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c 
b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c
index 82447d20fff..6383bec5ebc 100644
--- a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c
+++ b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c
@@ -9,7 +9,7 @@ void g();
 **     ...
 **     str     x30, \[sp\]
 **     sub     sp, sp, #4064
-**     str     xzr, \[sp\]
+**     str     xzr, \[sp, #?1024\]
 **     cbnz    w0, .*
 **     bl      g
 **     ...
@@ -50,7 +50,7 @@ int test1(int z) {
 **     ...
 **     str     x30, \[sp\]
 **     sub     sp, sp, #1040
-**     str     xzr, \[sp\]
+**     str     xzr, \[sp, #?1024\]
 **     cbnz    w0, .*
 **     bl      g
 **     ...
diff --git a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-19.c 
b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-19.c
index 73ac3e4e4eb..562039b5e9b 100644
--- a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-19.c
+++ b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-19.c
@@ -9,7 +9,7 @@ void g();
 **     ...
 **     str     x30, \[sp\]
 **     sub     sp, sp, #4064
-**     str     xzr, \[sp\]
+**     str     xzr, \[sp, #?1024\]
 **     cbnz    w0, .*
 **     bl      g
 **     ...
@@ -50,7 +50,7 @@ int test1(int z) {
 **     ...
 **     str     x30, \[sp\]
 **     sub     sp, sp, #1040
-**     str     xzr, \[sp\]
+**     str     xzr, \[sp, #?1024\]
 **     cbnz    w0, .*
 **     bl      g
 **     ...
-- 
2.25.1

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