Hi all,
In this final patch I adjust the troublesome gcc.target/arm/wmul-[123].c tests
to make them more helpful.
gcc.target/arm/wmul-[12].c may now generate either sign-extending multiplies
(+accumulate) or normal 32-bit multiplies since the arguments to the multiplies
are already sign-extended by preceding loads.
So for these tests the patch adds an -mtune option where we know the
sign-extending
form to be beneficial. This is, of course, reflected in the rtx costs that
guide the
RTL optimisers (after the fixes in patches 2 and 3).
For wmul-3.c we now generate objectively better code.
For the loop we previously generated:
.L2:
ldrh r1, [lr, #2]!
ldrh ip, [r0, #2]!
smulbb ip, r1, ip
sub r4, r4, ip
smulbb r1, r1, r1
sub r2, r2, r1
cmp lr, r5
bne .L2
and now we generate:
.L2:
ldrsh r1, [ip, #2]!
ldrsh r4, [r0, #2]!
mls lr, r1, r4, lr
mls r2, r1, r1, r2
cmp ip, r5
bne .L2
AFAICT the new sequence is better than the old one even for -mtune=cortex-a9
since it
contains two fewer instructions.
So this test is no longer a good source of getting smulbb instructions.
The proposed change in this patch is to greatly simplify it by writing a simple
enough
one-liner that we can always expect to be compiled into a single smulbb
instruction.
Tested on arm-none-eabi.
Ok for trunk?
Thanks,
Kyrill
2016-01-22 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
* gcc.target/arm/wmul-3.c: Simplify test to generate just
a single smulbb instruction.
* gcc.target/amr/wmul-1.c: Add -mtune=cortex-a9 to dg-options.
* gcc.target/amr/wmul-2.c: Likewise.
diff --git a/gcc/testsuite/gcc.target/arm/wmul-1.c b/gcc/testsuite/gcc.target/arm/wmul-1.c
index ddddd509fe645ea98877753773e7bcf9b6787897..c340f960fa444642fe18ae3bcac93d78fe9dc851 100644
--- a/gcc/testsuite/gcc.target/arm/wmul-1.c
+++ b/gcc/testsuite/gcc.target/arm/wmul-1.c
@@ -1,6 +1,6 @@
/* { dg-do compile } */
/* { dg-require-effective-target arm_dsp } */
-/* { dg-options "-O1 -fexpensive-optimizations" } */
+/* { dg-options "-O1 -fexpensive-optimizations -mtune=cortex-a9" } */
int mac(const short *a, const short *b, int sqr, int *sum)
{
diff --git a/gcc/testsuite/gcc.target/arm/wmul-2.c b/gcc/testsuite/gcc.target/arm/wmul-2.c
index 2ea55f9fbe12f74f38754cb72be791fd6e9495f4..bd2435c9113a82d2e102b545b3141cbda9ba326d 100644
--- a/gcc/testsuite/gcc.target/arm/wmul-2.c
+++ b/gcc/testsuite/gcc.target/arm/wmul-2.c
@@ -1,6 +1,6 @@
/* { dg-do compile } */
/* { dg-require-effective-target arm_dsp } */
-/* { dg-options "-O1 -fexpensive-optimizations" } */
+/* { dg-options "-O1 -fexpensive-optimizations -mtune=cortex-a9" } */
void vec_mpy(int y[], const short x[], short scaler)
{
diff --git a/gcc/testsuite/gcc.target/arm/wmul-3.c b/gcc/testsuite/gcc.target/arm/wmul-3.c
index 144b553082e6158701639f05929987de01e7125a..87eba740142a80a1dc1979b4e79d9272a839e7b2 100644
--- a/gcc/testsuite/gcc.target/arm/wmul-3.c
+++ b/gcc/testsuite/gcc.target/arm/wmul-3.c
@@ -1,19 +1,11 @@
/* { dg-do compile } */
/* { dg-require-effective-target arm_dsp } */
-/* { dg-options "-O1 -fexpensive-optimizations" } */
+/* { dg-options "-O" } */
-int mac(const short *a, const short *b, int sqr, int *sum)
+int
+foo (int a, int b)
{
- int i;
- int dotp = *sum;
-
- for (i = 0; i < 150; i++) {
- dotp -= b[i] * a[i];
- sqr -= b[i] * b[i];
- }
-
- *sum = dotp;
- return sqr;
+ return (short) a * (short) b;
}
-/* { dg-final { scan-assembler-times "smulbb" 2 } } */
+/* { dg-final { scan-assembler-times "smulbb" 1 } } */
