3 files changed, 44 insertions, 0 deletions
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index cffb945..7feff77 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -6749,6 +6749,14 @@ aarch64_layout_frame (void)
 			+ frame.sve_callee_adjust
 			+ frame.final_adjust, frame.frame_size));
 
+  if (!frame.emit_frame_chain && frame.callee_adjust == 0)
+    {
+      /* We've decided not to associate any register saves with the initial
+	 stack allocation.  */
+      frame.wb_candidate1 = INVALID_REGNUM;
+      frame.wb_candidate2 = INVALID_REGNUM;
+    }
+
   frame.laid_out = true;
 }
 
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index 24767c7..2be52fd 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -842,6 +842,23 @@ struct GTY (()) aarch64_frame
   /* Store FP,LR and setup a frame pointer.  */
   bool emit_frame_chain;
 
+  /* In each frame, we can associate up to two register saves with the
+     initial stack allocation.  This happens in one of two ways:
+
+     (1) Using an STR or STP with writeback to perform the initial
+	 stack allocation.  When EMIT_FRAME_CHAIN, the registers will
+	 be those needed to create a frame chain.
+
+	 Indicated by CALLEE_ADJUST != 0.
+
+     (2) Using a separate STP to set up the frame record, after the
+	 initial stack allocation but before setting up the frame pointer.
+	 This is used if the offset is too large to use writeback.
+
+	 Indicated by CALLEE_ADJUST == 0 && EMIT_FRAME_CHAIN.
+
+     These fields indicate which registers we've decided to handle using
+     (1) or (2), or INVALID_REGNUM if none.  */
   unsigned wb_candidate1;
   unsigned wb_candidate2;
 
diff --git a/gcc/testsuite/gcc.target/aarch64/shrink_wrap_1.c b/gcc/testsuite/gcc.target/aarch64/shrink_wrap_1.c
new file mode 100644
index 0000000..ab7cd74
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/shrink_wrap_1.c
@@ -0,0 +1,19 @@
+/* { dg-do compile { target { aarch64*-*-* } } } */
+/* { dg-options "-O2" } */
+/* { dg-final { check-function-bodies "**" "" } } */
+
+/*
+** foo:
+**	...
+**	str	d8, \[sp\]
+**	ldr	d8, \[sp\]
+**	...
+*/
+void
+foo (int x)
+{
+  int tmp[0x1000];
+  asm volatile ("" : "=m" (tmp));
+  if (x == 1)
+    asm volatile ("" ::: "d8");
+}