x86: Properly check saved register CFA offset

X86 prologue saves register at CFA offset.  Since its location on stack
is computed as CFA - its CFA_OFFSET, CFA_OFFSET points the end of the
saved register area on stack.  This patch updates sp_valid_at and
fp_valid_at to properly check saved register CFA offset.

gcc/

	PR target/81563
	* config/i386/i386.c (sp_valid_at): Properly check CFA offset.
	(fp_valid_at): Likewise.

gcc/testsuite/

	PR target/81563
	* gcc.target/i386/pr81563.c: New test

From-SVN: r250587

gcc/ChangeLog

+2017-07-26  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR target/81563
+	* config/i386/i386.c (sp_valid_at): Properly check CFA offset.
+	(fp_valid_at): Likewise.
+
 2017-07-26  James Greenhalgh  <james.greenhalgh@arm.com>
 
 	* config/aarch64/aarch64.c (cortexa57_addrcost_table): Remove.

gcc/config/i386/i386.c

@@ -13102,24 +13102,26 @@ choose_baseaddr_len (unsigned int regno, HOST_WIDE_INT offset)
   return len;
 }
 
-/* Determine if the stack pointer is valid for accessing the cfa_offset.  */
+/* Determine if the stack pointer is valid for accessing the cfa_offset.
+   The register is saved at CFA - CFA_OFFSET.  */
 
 static inline bool
 sp_valid_at (HOST_WIDE_INT cfa_offset)
 {
   const struct machine_frame_state &fs = cfun->machine->fs;
   return fs.sp_valid && !(fs.sp_realigned
-			  && cfa_offset < fs.sp_realigned_offset);
+			  && cfa_offset <= fs.sp_realigned_offset);
 }
 
-/* Determine if the frame pointer is valid for accessing the cfa_offset.  */
+/* Determine if the frame pointer is valid for accessing the cfa_offset.
+   The register is saved at CFA - CFA_OFFSET.  */
 
 static inline bool
 fp_valid_at (HOST_WIDE_INT cfa_offset)
 {
   const struct machine_frame_state &fs = cfun->machine->fs;
   return fs.fp_valid && !(fs.sp_valid && fs.sp_realigned
-			  && cfa_offset >= fs.sp_realigned_offset);
+			  && cfa_offset > fs.sp_realigned_offset);
 }
 
 /* Choose a base register based upon alignment requested, speed and/or

gcc/testsuite/ChangeLog

+2017-07-26  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR target/81563
+	* gcc.target/i386/pr81563.c: New test
+
 2017-07-26  Wilco Dijkstra  <wdijkstr@arm.com>
 
 	PR target/79041

gcc/testsuite/gcc.target/i386/pr81563.c

+/* { dg-do compile { target ia32 } } */
+/* { dg-options "-O2 -maccumulate-outgoing-args -mincoming-stack-boundary=2 -mpreferred-stack-boundary=3 -mregparm=3 -mtune-ctrl=epilogue_using_move" } */
+
+extern void bar (long long int, int);
+
+long long int
+fn1 (long long int x)
+{
+  bar (x, 1);
+  return x;
+}
+
+/* { dg-final { scan-assembler-times "movl\[\\t \]*-8\\(%ebp\\),\[\\t \]*%esi" 1 } } */
+/* { dg-final { scan-assembler-times "movl\[\\t \]*-4\\(%ebp\\),\[\\t \]*%edi" 1 } } */