[PATCH, MIPS] Frame header optimization for MIPS O32 ABI

[Steve Ellcey]

On Tue, 2015-10-06 at 12:02 +0000, Moore, Catherine wrote:

> > Moore, Catherine <Catherine_Moore@mentor.com> writes:
> > > The patch itself looks good, but the tests that you added need a little more
> > work.

Here is a new patch for just the tests.  I added NOMIPS16 and the
-mabi=32 flag as Matthew suggested and I also added -mno-abicalls.

Without the -mno-abicalls the MIPS linux compiler defaulted to
-mabicalls and allocated 32 bytes without the optimization and the MIPS
elf compiler defaulted to -mno-abicalls and allocated 24 bytes without
the optimization.  This synchronizes them so they both allocate 24 bytes
without the optimization and 8 bytes with it.  Everything should pass
now, it passed for me using mips-mti-linux-gnu and mips-mti-elf.

Steve Ellcey
sellcey@imgtec.com


2015-10-06  Steve Ellcey  <sellcey@imgtec.com>

	* gcc.target/mips/mips.exp (mips_option_groups): Add -mframe-header-opt
	and -mno-frame-header-opt options.
	* gcc.target/mips/frame-header-1.c: New file.
	* gcc.target/mips/frame-header-2.c: New file.
	* gcc.target/mips/frame-header-3.c: New file.


diff --git a/gcc/testsuite/gcc.target/mips/frame-header-1.c b/gcc/testsuite/gcc.target/mips/frame-header-1.c
new file mode 100644
index 0000000..971656d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/mips/frame-header-1.c
@@ -0,0 +1,21 @@
+/* Verify that we do not optimize away the frame header in foo when using
+   -mno-frame-header-opt by checking the stack pointer increment done in
+   that function.  Without the optimization foo should increment the stack
+   by 24 bytes, with the optimization it would only be 8 bytes.  */
+
+/* { dg-do compile } */
+/* { dg-options "-mno-frame-header-opt -mabi=32 -mno-abicalls" } */
+/* { dg-skip-if "code quality test" { *-*-* } { "-O0" } { "" } } */
+/* { dg-final { scan-assembler "\taddiu\t\\\$sp,\\\$sp,-24" } } */
+
+NOMIPS16 void __attribute__((noinline))
+bar (int* a)
+{
+  *a = 1;
+}
+
+NOMIPS16 void
+foo (int a)
+{
+  bar (&a);
+}
diff --git a/gcc/testsuite/gcc.target/mips/frame-header-2.c b/gcc/testsuite/gcc.target/mips/frame-header-2.c
new file mode 100644
index 0000000..0e86bc9
--- /dev/null
+++ b/gcc/testsuite/gcc.target/mips/frame-header-2.c
@@ -0,0 +1,21 @@
+/* Verify that we do optimize away the frame header in foo when using
+   -mframe-header-opt by checking the stack pointer increment done in
+   that function.  Without the optimization foo should increment the
+   stack by 24 bytes, with the optimization it would only be 8 bytes.  */
+
+/* { dg-do compile } */
+/* { dg-options "-mframe-header-opt -mabi=32 -mno-abicalls" } */
+/* { dg-skip-if "code quality test" { *-*-* } { "-O0" } { "" } } */
+/* { dg-final { scan-assembler "\taddiu\t\\\$sp,\\\$sp,-8" } } */
+
+NOMIPS16 void __attribute__((noinline))
+bar (int* a)
+{
+  *a = 1;
+}
+
+NOMIPS16 void
+foo (int a)
+{
+  bar (&a);
+}
diff --git a/gcc/testsuite/gcc.target/mips/frame-header-3.c b/gcc/testsuite/gcc.target/mips/frame-header-3.c
new file mode 100644
index 0000000..2a8c515
--- /dev/null
+++ b/gcc/testsuite/gcc.target/mips/frame-header-3.c
@@ -0,0 +1,22 @@
+/* Verify that we do not optimize away the frame header in foo when using
+   -mframe-header-opt but are calling a weak function that may be overridden
+   by a different function that does need the frame header.  Without the
+   optimization foo should increment the stack by 24 bytes, with the
+   optimization it would only be 8 bytes.  */
+
+/* { dg-do compile } */
+/* { dg-options "-mframe-header-opt -mabi=32 -mno-abicalls" } */
+/* { dg-skip-if "code quality test" { *-*-* } { "-O0" } { "" } } */
+/* { dg-final { scan-assembler "\taddiu\t\\\$sp,\\\$sp,-24" } } */
+
+NOMIPS16 void __attribute__((noinline, weak))
+bar (int* a)
+{
+  *a = 1;
+}
+
+void
+NOMIPS16 foo (int a)
+{
+  bar (&a);
+}
diff --git a/gcc/testsuite/gcc.target/mips/mips.exp b/gcc/testsuite/gcc.target/mips/mips.exp
index 42e7fff..0f2d6a2 100644
--- a/gcc/testsuite/gcc.target/mips/mips.exp
+++ b/gcc/testsuite/gcc.target/mips/mips.exp
@@ -256,6 +256,7 @@ set mips_option_groups {
     maddps "HAS_MADDPS"
     lsa "(|!)HAS_LSA"
     section_start "-Wl,--section-start=.*"
+    frame-header "-mframe-header-opt|-mno-frame-header-opt"
 }
 
 for { set option 0 } { $option < 32 } { incr option } {