Hi,
The patch removes mode promotion for pseudos on rs6000 target.
The attachments are the patch diff and change log file.
Bootstrapped and tested on powerpc64le-linux and powerpc64-linux
(with both m32 and m64) with no regressions. Is this okay for trunk? Any
recommendations? Thanks a lot.
rs6000 has instructions that can do almost everything 32 bit
at least as efficiently as corresponding 64 bit things. The
mode promotion can be defered to when a wide mode is necessary.
So it helps a lot not promote mode for pseudos. SPECint test
shows that the overall performance improvement (by geomean) is
more than 2% with this patch.
testsuite/gcc.target/powerpc/not-promote-mode.c illustrates how
the patch eliminates the redundant extensions and do further
optimization by disabling mode promotion for pseduos.
* config/rs6000/rs6000.h (PROMOTE_MODE): Remove.
* testsuite/gcc.target/powerpc/not-promote-mode.c: New.
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index 233a92baf3c..f6485fcacf5 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -666,17 +666,6 @@ extern unsigned char rs6000_recip_bits[];
/* Target machine storage layout. */
-/* Define this macro if it is advisable to hold scalars in registers
- in a wider mode than that declared by the program. In such cases,
- the value is constrained to be within the bounds of the declared
- type, but kept valid in the wider mode. The signedness of the
- extension may differ from that of the type. */
-
-#define PROMOTE_MODE(MODE,UNSIGNEDP,TYPE) \
- if (GET_MODE_CLASS (MODE) == MODE_INT \
- && GET_MODE_SIZE (MODE) < (TARGET_32BIT ? 4 : 8)) \
- (MODE) = TARGET_32BIT ? SImode : DImode;
-
/* Define this if most significant bit is lowest numbered
in instructions that operate on numbered bit-fields. */
/* That is true on RS/6000. */
diff --git a/gcc/testsuite/gcc.target/powerpc/not-promote-mode.c
b/gcc/testsuite/gcc.target/powerpc/not-promote-mode.c
new file mode 100644
index 00000000000..4d29ebe8b87
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/not-promote-mode.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { powerpc*-*-* && lp64 } } } */
+/* { dg-options "-O2" } */
+
+extern void bar ();
+
+void foo ()
+{
+ int i;
+ for (i = 0; i < 10000; i++)
+ bar ();
+}
+
+/* { dg-final { scan-assembler-not {\mrldicl\M} } } */
