https://gcc.gnu.org/g:aeaa1945bca2afab4a66f6749a5cf323d7a6f28f
commit aeaa1945bca2afab4a66f6749a5cf323d7a6f28f
Author: Michael Meissner <meiss...@linux.ibm.com>
Date: Mon Dec 2 15:01:33 2024 -0500
Do not allow -mvsx to boost processor to power7.
This patch restructures the code so that -mvsx for example will not silently
convert the processor to power7. The user must now use -mcpu=power7 or
higher.
This means if the user does -mvsx and the default processor does not have
VSX
support, it will be an error.
I have built both big endian and little endian bootstrap compilers and there
were no regressions.
I updated the 2 tests that used -mvsx to raise the cpu to power7, and the
test
case that checks if -mno-vsx produces the expected warning.
Note, Peter had some questions about one of the tests in the previous
version of
the patch. The test is still the same in this patch. But the code for
preventing -mvsx is different from the previous patch, and I wanted to get
that
patch for review before stage1 closes.
Can I install this patch on the GCC 15 trunk?
2024-12-02 Michael Meissner <meiss...@linux.ibm.com>
gcc/
* config/rs6000/rs6000.cc (rs6000_option_override_internal): Check
if
the user asked for VSX instructions whether the cpu was at least
power7.
gcc/testsuite/
* gcc.target/powerpc/ppc-target-4.c: Rewrite the test to add
cpu=power7
when we need to add VSX support. Add test for adding cpu=power7
no-vsx
to generate only Altivec instructions.
* gcc.target/powerpc/pr115688.c: Add cpu=power7 in target
__attribute__
when requesting VSX instructions.
* gcc.target/powerpc/pr87496-1.c: Update options to use
-mdejagnu-cpu=power6 to get the appropriate error message.
Diff:
---
gcc/config/rs6000/rs6000.cc | 7 +++++
gcc/testsuite/gcc.target/powerpc/ppc-target-4.c | 38 +++++++++++++++++++------
gcc/testsuite/gcc.target/powerpc/pr115688.c | 3 +-
gcc/testsuite/gcc.target/powerpc/pr87496-1.c | 2 +-
4 files changed, 39 insertions(+), 11 deletions(-)
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 83e8141cf98c..5c64310b16c1 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -3862,6 +3862,13 @@ rs6000_option_override_internal (bool global_init_p)
rs6000_isa_flags &= ~OPTION_MASK_VSX;
rs6000_isa_flags_explicit |= OPTION_MASK_VSX;
}
+ else if (!TARGET_POWER7)
+ {
+ if (explicit_vsx_p)
+ error ("%<-mvsx%> requires at least %<-mcpu=power%>");
+ rs6000_isa_flags &= ~OPTION_MASK_VSX;
+ rs6000_isa_flags_explicit |= OPTION_MASK_VSX;
+ }
}
/* If hard-float/altivec/vsx were explicitly turned off then don't allow
diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-target-4.c
b/gcc/testsuite/gcc.target/powerpc/ppc-target-4.c
index feef76db4618..5e2ecf34f249 100644
--- a/gcc/testsuite/gcc.target/powerpc/ppc-target-4.c
+++ b/gcc/testsuite/gcc.target/powerpc/ppc-target-4.c
@@ -2,7 +2,7 @@
/* { dg-skip-if "" { powerpc*-*-darwin* } } */
/* { dg-require-effective-target powerpc_fprs } */
/* { dg-options "-O2 -ffast-math -mdejagnu-cpu=power5 -mno-altivec
-mabi=altivec -fno-unroll-loops" } */
-/* { dg-final { scan-assembler-times "vaddfp" 1 } } */
+/* { dg-final { scan-assembler-times "vaddfp" 2 } } */
/* { dg-final { scan-assembler-times "xvaddsp" 1 } } */
/* { dg-final { scan-assembler-times "fadds" 1 } } */
@@ -18,10 +18,6 @@
#error "__VSX__ should not be defined."
#endif
-#pragma GCC target("altivec,vsx")
-#include <altivec.h>
-#pragma GCC reset_options
-
#pragma GCC push_options
#pragma GCC target("altivec,no-vsx")
@@ -33,6 +29,7 @@
#error "__VSX__ should not be defined."
#endif
+/* Altivec build, generate vaddfp. */
void
av_add (vector float *a, vector float *b, vector float *c)
{
@@ -40,10 +37,11 @@ av_add (vector float *a, vector float *b, vector float *c)
unsigned long n = SIZE / 4;
for (i = 0; i < n; i++)
- a[i] = vec_add (b[i], c[i]);
+ a[i] = b[i] + c[i];
}
-#pragma GCC target("vsx")
+/* cpu=power7 must be used to enable VSX. */
+#pragma GCC target("cpu=power7,vsx")
#ifndef __ALTIVEC__
#error "__ALTIVEC__ should be defined."
@@ -53,6 +51,7 @@ av_add (vector float *a, vector float *b, vector float *c)
#error "__VSX__ should be defined."
#endif
+/* VSX build on power7, generate xsaddsp. */
void
vsx_add (vector float *a, vector float *b, vector float *c)
{
@@ -60,11 +59,31 @@ vsx_add (vector float *a, vector float *b, vector float *c)
unsigned long n = SIZE / 4;
for (i = 0; i < n; i++)
- a[i] = vec_add (b[i], c[i]);
+ a[i] = b[i] + c[i];
+}
+
+#pragma GCC target("cpu=power7,no-vsx")
+
+#ifndef __ALTIVEC__
+#error "__ALTIVEC__ should be defined."
+#endif
+
+#ifdef __VSX__
+#error "__VSX__ should not be defined."
+#endif
+
+/* Altivec build on power7 with no VSX, generate vaddfp. */
+void
+av2_add (vector float *a, vector float *b, vector float *c)
+{
+ unsigned long i;
+ unsigned long n = SIZE / 4;
+
+ for (i = 0; i < n; i++)
+ a[i] = b[i] + c[i];
}
#pragma GCC pop_options
-#pragma GCC target("no-vsx,no-altivec")
#ifdef __ALTIVEC__
#error "__ALTIVEC__ should not be defined."
@@ -74,6 +93,7 @@ vsx_add (vector float *a, vector float *b, vector float *c)
#error "__VSX__ should not be defined."
#endif
+/* Default power5 build, generate scalar fadds. */
void
norm_add (float *a, float *b, float *c)
{
diff --git a/gcc/testsuite/gcc.target/powerpc/pr115688.c
b/gcc/testsuite/gcc.target/powerpc/pr115688.c
index 5222e66ef170..00c7c301436a 100644
--- a/gcc/testsuite/gcc.target/powerpc/pr115688.c
+++ b/gcc/testsuite/gcc.target/powerpc/pr115688.c
@@ -7,7 +7,8 @@
/* Verify there is no ICE under 32 bit env. */
-__attribute__((target("vsx")))
+/* cpu=power7 must be used to enable VSX. */
+__attribute__((target("cpu=power7,vsx")))
int test (void)
{
return 0;
diff --git a/gcc/testsuite/gcc.target/powerpc/pr87496-1.c
b/gcc/testsuite/gcc.target/powerpc/pr87496-1.c
index b8d00286256a..2029ecacaf9b 100644
--- a/gcc/testsuite/gcc.target/powerpc/pr87496-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/pr87496-1.c
@@ -2,7 +2,7 @@
/* { dg-do compile { target { powerpc*-*-* && lp64 } } } */
/* { dg-skip-if "" { powerpc*-*-darwin* } } */
/* { dg-require-effective-target longdouble128 } */
-/* { dg-options "-O2 -mdejagnu-cpu=power7 -mabi=ieeelongdouble -mno-popcntd
-Wno-psabi" } */
+/* { dg-options "-O2 -mdejagnu-cpu=power6 -mabi=ieeelongdouble -Wno-psabi" } */
int i;
