Software mitigation: Disable gather generation in vectorization for GDS affected...

For more details of GDS (Gather Data Sampling), refer to
https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/advisory-guidance/gather-data-sampling.html

After microcode update, there's performance regression. To avoid that,
the patch disables gather generation in autovectorization but uses
gather scalar emulation instead.

gcc/ChangeLog:

	* config/i386/i386-options.cc (m_GDS): New macro.
	* config/i386/x86-tune.def (X86_TUNE_USE_GATHER_2PARTS): Don't
	enable for m_GDS.
	(X86_TUNE_USE_GATHER_4PARTS): Ditto.
	(X86_TUNE_USE_GATHER): Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/avx2-gather-2.c: Adjust options to keep
	gather vectorization.
	* gcc.target/i386/avx2-gather-6.c: Ditto.
	* gcc.target/i386/avx512f-pr88464-1.c: Ditto.
	* gcc.target/i386/avx512f-pr88464-5.c: Ditto.
	* gcc.target/i386/avx512vl-pr88464-1.c: Ditto.
	* gcc.target/i386/avx512vl-pr88464-11.c: Ditto.
	* gcc.target/i386/avx512vl-pr88464-3.c: Ditto.
	* gcc.target/i386/avx512vl-pr88464-9.c: Ditto.
	* gcc.target/i386/pr88531-1b.c: Ditto.
	* gcc.target/i386/pr88531-1c.c: Ditto.

diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
index 127ee24203cd9e8cb48bd44c5a2b05820ba752ce..e6ba33c370dc9de35e20c2e105256d099009eff6 100644 (file)
--- a/gcc/config/i386/i386-options.cc
+++ b/gcc/config/i386/i386-options.cc
@@ -141,6 +141,11 @@ along with GCC; see the file COPYING3.  If not see
 #define m_ARROWLAKE (HOST_WIDE_INT_1U<<PROCESSOR_ARROWLAKE)
 #define m_CORE_ATOM (m_SIERRAFOREST | m_GRANDRIDGE)
 #define m_INTEL (HOST_WIDE_INT_1U<<PROCESSOR_INTEL)
+/* Gather Data Sampling / CVE-2022-40982 / INTEL-SA-00828.
+   Software mitigation.  */
+#define m_GDS (m_SKYLAKE | m_SKYLAKE_AVX512 | m_CANNONLAKE \
+              | m_ICELAKE_CLIENT | m_ICELAKE_SERVER | m_CASCADELAKE \
+              | m_TIGERLAKE | m_COOPERLAKE | m_ROCKETLAKE)
 
 #define m_LUJIAZUI (HOST_WIDE_INT_1U<<PROCESSOR_LUJIAZUI)
 

diff --git a/gcc/config/i386/x86-tune.def b/gcc/config/i386/x86-tune.def
index 40e04ecddbf8a4d16aaa1b2ae8e40186db63272e..22d26bb0030c70e2dfcdf463c5287d2c291f4af7 100644 (file)
--- a/gcc/config/i386/x86-tune.def
+++ b/gcc/config/i386/x86-tune.def
@@ -491,7 +491,7 @@ DEF_TUNE (X86_TUNE_AVOID_4BYTE_PREFIXES, "avoid_4byte_prefixes",
    elements.  */
 DEF_TUNE (X86_TUNE_USE_GATHER_2PARTS, "use_gather_2parts",
          ~(m_ZNVER1 | m_ZNVER2 | m_ZNVER3 | m_ZNVER4 | m_ALDERLAKE
-           | m_ARROWLAKE | m_CORE_ATOM | m_GENERIC))
+           | m_ARROWLAKE | m_CORE_ATOM | m_GENERIC | m_GDS))
 
 /* X86_TUNE_USE_SCATTER_2PARTS: Use scater instructions for vectors with 2
    elements.  */
@@ -502,7 +502,7 @@ DEF_TUNE (X86_TUNE_USE_SCATTER_2PARTS, "use_scatter_2parts",
    elements.  */
 DEF_TUNE (X86_TUNE_USE_GATHER_4PARTS, "use_gather_4parts",
          ~(m_ZNVER1 | m_ZNVER2 | m_ZNVER3 | m_ZNVER4 | m_ALDERLAKE
-           | m_ARROWLAKE | m_CORE_ATOM | m_GENERIC))
+           | m_ARROWLAKE | m_CORE_ATOM | m_GENERIC | m_GDS))
 
 /* X86_TUNE_USE_SCATTER_4PARTS: Use scater instructions for vectors with 4
    elements.  */
@@ -513,7 +513,7 @@ DEF_TUNE (X86_TUNE_USE_SCATTER_4PARTS, "use_scatter_4parts",
    elements.  */
 DEF_TUNE (X86_TUNE_USE_GATHER, "use_gather",
          ~(m_ZNVER1 | m_ZNVER2 | m_ZNVER4 | m_ALDERLAKE | m_ARROWLAKE
-           | m_CORE_ATOM | m_GENERIC))
+           | m_CORE_ATOM | m_GENERIC | m_GDS))
 
 /* X86_TUNE_USE_SCATTER: Use scater instructions for vectors with 8 or more
    elements.  */

diff --git a/gcc/testsuite/gcc.target/i386/avx2-gather-2.c b/gcc/testsuite/gcc.target/i386/avx2-gather-2.c
index ad5ef73107c1a5fa0641562adac264fd2fe182c6..978924b0f57679e703f9b7671998381e3a038809 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/avx2-gather-2.c
+++ b/gcc/testsuite/gcc.target/i386/avx2-gather-2.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O3 -fdump-tree-vect-details -march=skylake" } */
+/* { dg-options "-O3 -fdump-tree-vect-details -march=skylake -mtune=haswell" } */
 
 #include "avx2-gather-1.c"
 

diff --git a/gcc/testsuite/gcc.target/i386/avx2-gather-6.c b/gcc/testsuite/gcc.target/i386/avx2-gather-6.c
index 47a95dbe9891270a3c23046a45c4e5a1244dbe5c..0bb40ac14eb7f982ec44d52a4f327338f99797c5 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/avx2-gather-6.c
+++ b/gcc/testsuite/gcc.target/i386/avx2-gather-6.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O3 -mavx2 -fno-common -fdump-tree-vect-details -mtune=skylake -fno-split-loops" } */
+/* { dg-options "-O3 -mavx2 -fno-common -fdump-tree-vect-details  -mtune=haswell -fno-split-loops" } */
 
 #include "avx2-gather-5.c"
 

diff --git a/gcc/testsuite/gcc.target/i386/avx512f-pr88464-1.c b/gcc/testsuite/gcc.target/i386/avx512f-pr88464-1.c
index 06d21bb0129904a66c1ae2a30d2cb29b0ec43fa6..d1a2298618ea3a62fb465634433089c602bc3049 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/avx512f-pr88464-1.c
+++ b/gcc/testsuite/gcc.target/i386/avx512f-pr88464-1.c
@@ -1,6 +1,6 @@
 /* PR tree-optimization/88464 */
 /* { dg-do compile } */
-/* { dg-options "-O3 -mavx512f -mprefer-vector-width=512 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
+/* { dg-options "-O3 -mavx512f -mprefer-vector-width=512 -mtune=haswell -fdump-tree-vect-details" } */
 /* { dg-final { scan-tree-dump-times "loop vectorized using 64 byte vectors" 4 "vect" } } */
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
 

diff --git a/gcc/testsuite/gcc.target/i386/avx512f-pr88464-5.c b/gcc/testsuite/gcc.target/i386/avx512f-pr88464-5.c
index 462e951fdc17754b406477ac93aa7b1f38ec3616..d7b0b2b28cb720b53f7820a15336fc6980db3372 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/avx512f-pr88464-5.c
+++ b/gcc/testsuite/gcc.target/i386/avx512f-pr88464-5.c
@@ -1,6 +1,6 @@
 /* PR tree-optimization/88464 */
 /* { dg-do compile } */
-/* { dg-options "-O3 -mavx512f -mprefer-vector-width=512 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
+/* { dg-options "-O3 -mavx512f -mprefer-vector-width=512 -mtune=haswell -fdump-tree-vect-details" } */
 /* { dg-final { scan-tree-dump-times "loop vectorized using 64 byte vectors" 4 "vect" } } */
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
 

diff --git a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-1.c b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-1.c
index 55a28dddbf84ff0faf74177f0ab7667789a031a2..07439185ec1720c1bec2e66b3948e2f3bf32ed78 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-1.c
+++ b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-1.c
@@ -1,6 +1,6 @@
 /* PR tree-optimization/88464 */
 /* { dg-do compile } */
-/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=256 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
+/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=256 -mtune=haswell -fdump-tree-vect-details" } */
 /* { dg-final { scan-tree-dump-times "loop vectorized using 32 byte vectors" 4 "vect" } } */
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
 

diff --git a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-11.c b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-11.c
index 9696008855da59bcd593555abf7c5603e387019e..3a98108279a4b93c841ef1c1abb2144ebd82e678 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-11.c
+++ b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-11.c
@@ -1,6 +1,6 @@
 /* PR tree-optimization/88464 */
 /* { dg-do compile } */
-/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=128 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
+/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=128 -mtune=haswell -fdump-tree-vect-details" } */
 /* { dg-final { scan-tree-dump-times "loop vectorized using 16 byte vectors" 4 "vect" } } */
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
 

diff --git a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-3.c b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-3.c
index 6b0c8a85957f0f8a83453c26552ee41dd54c857b..ac669e0481290f6d1c9e756bfc3275ec6a4049d5 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-3.c
+++ b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-3.c
@@ -1,6 +1,6 @@
 /* PR tree-optimization/88464 */
 /* { dg-do compile } */
-/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=128 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
+/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=128 -mtune=haswell -fdump-tree-vect-details" } */
 /* { dg-final { scan-tree-dump-times "loop vectorized using 16 byte vectors" 4 "vect" } } */
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
 

diff --git a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-9.c b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-9.c
index 3af568ab32377e959fb0752691489909d7180b8d..14a1083b6d1115dcbe115af83ce0005526c094f7 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-9.c
+++ b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-9.c
@@ -1,6 +1,6 @@
 /* PR tree-optimization/88464 */
 /* { dg-do compile } */
-/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=256 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
+/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=256 -mtune=haswell -fdump-tree-vect-details" } */
 /* { dg-final { scan-tree-dump-times "loop vectorized using 32 byte vectors" 4 "vect" } } */
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
 

diff --git a/gcc/testsuite/gcc.target/i386/pr88531-1b.c b/gcc/testsuite/gcc.target/i386/pr88531-1b.c
index 812c8a10fab111c9a7a9c0d970f8852b5aaf3501..e6df789de9007b9f6a4331e2560b6f0c4d2fa5f4 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/pr88531-1b.c
+++ b/gcc/testsuite/gcc.target/i386/pr88531-1b.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O3 -march=skylake -mfpmath=sse" } */
+/* { dg-options "-O3 -march=skylake -mfpmath=sse -mtune=haswell" } */
 
 #include "pr88531-1a.c"
 

diff --git a/gcc/testsuite/gcc.target/i386/pr88531-1c.c b/gcc/testsuite/gcc.target/i386/pr88531-1c.c
index 43fc5913ed36dfee2e001df6d3ffdaf188481064..a093c87c01fdb4152f4e98254cd6cc418eb9b9c3 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/pr88531-1c.c
+++ b/gcc/testsuite/gcc.target/i386/pr88531-1c.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O3 -march=skylake-avx512 -mfpmath=sse" } */
+/* { dg-options "-O3 -march=skylake-avx512 -mfpmath=sse -mtune=haswell" } */
 
 #include "pr88531-1a.c"