gcn: Add missing GFX9_4_GENERIC, OpenMP context-selector update

The definition for gfx942 and gfx950 missed the GFX9_4_GENERIC
family flag.

For OpenMP context selectors: The t-omp-device file missed the
generic selectors.

Additionally, there is now a note in the OpenMP documentation that
there is a one-to-one match for ISA names, ignoring any compatibility.
For instance, for Nvidia GPUs 'isa("sm_70")' is only true when compiling
for 'sm_70', even though sm < 7.0 code also runs on sm_70 hardware.
And, for AMD GPUs, gfx9-4-generic neither matches 'gfx942'
(even though such generic code runs on gfx942) - nor the reverse
(although all gfx9-4-generic code runs on gfx942).

gcc/ChangeLog:

	* config/gcn/gcn-devices.def (gfx942, gfx950): Set generic name
	to GFX9_4_GENERIC.
	* config/gcn/t-omp-device: Include generic names for OpenMP's
	ISA trait.

libgomp/ChangeLog:

	* libgomp.texi (OpenMP Context Selectors): Add note that there is
	currently an exact match between ISA and compilation, ignoring
	compatibilities in both ways.
	* testsuite/libgomp.c/declare-variant-4.h: Add missing variant
	functions for specific and generic AMD GPUs.
	* testsuite/libgomp.c/declare-variant-4-gfx10-3-generic.c: New test.
	* testsuite/libgomp.c/declare-variant-4-gfx11-generic.c: New test.
	* testsuite/libgomp.c/declare-variant-4-gfx9-4-generic.c: New test.
	* testsuite/libgomp.c/declare-variant-4-gfx9-generic.c: New test.

gcc/config/gcn/gcn-devices.def

@@ -179,7 +179,7 @@ GCN_DEVICE(gfx942, GFX942, 0x4c, ISA_CDNA3,
 	   /* Max ISA VGPRs */ 512,
 	   /* Generic code obj version */ 0,  /* non-generic */
 	   /* Architecture Family */ GFX9,
-	   /* Generic Name */ NONE
+	   /* Generic Name */ GFX9_4_GENERIC
 	   )
 
 GCN_DEVICE(gfx950, GFX950, 0x4f, ISA_CDNA3,
@@ -190,7 +190,7 @@ GCN_DEVICE(gfx950, GFX950, 0x4f, ISA_CDNA3,
 	   /* Max ISA VGPRs */ 512,
 	   /* Generic code obj version */ 0,  /* non-generic */
 	   /* Architecture Family */ GFX9,
-	   /* Generic Name */ NONE
+	   /* Generic Name */ GFX9_4_GENERIC
 	   )
 
 GCN_DEVICE(gfx9-generic, GFX9_GENERIC, 0x051, ISA_GCN5,

gcc/config/gcn/t-omp-device

@@ -1,4 +1,4 @@
 omp-device-properties-gcn: $(srcdir)/config/gcn/gcn-devices.def
 	echo kind: gpu > $@
 	echo arch: amdgcn gcn >> $@
-	echo isa: `grep -o -P '(?<=GCN_DEVICE\()gfx[0-9a-f]+(?=,)' $<` >> $@
+	echo isa: `grep -o -P '(?<=GCN_DEVICE\()gfx[-0-9a-f]+(|-generic)(?=,)' $<` >> $@

libgomp/libgomp.texi

@@ -6824,6 +6824,13 @@ the following traits are supported in addition; while OpenMP is supported
 on more architectures, GCC currently does not match any @code{arch} or
 @code{isa} traits for those.
 
+Note that for AMD GCN and Nvidia PTX, the @code{isa} is currently an
+exact match between the compiled-for ISA architecture and the matching
+@code{isa} trait value.  For instance, when compiling for @code{gfx942},
+the @code{isa} trait value @code{gfx9-4-generic} is not matched and,
+likewise, @code{gfx942} is not matched when compiling for its generic
+architecture.
+
 @multitable @columnfractions .65 .30
 @headitem @code{arch} @tab @code{isa}
 @item @code{x86}, @code{x86_64}, @code{i386}, @code{i486},

libgomp/testsuite/libgomp.c/declare-variant-4-gfx10-3-generic.c

@@ -0,0 +1,8 @@
+/* { dg-do link { target { offload_target_amdgcn } } } */
+/* { dg-additional-options -foffload=amdgcn-amdhsa } */
+/* { dg-additional-options -foffload=-march=gfx10-3-generic } */
+/* { dg-additional-options "-foffload=-fdump-tree-optimized" } */
+
+#include "declare-variant-4.h"
+
+/* { dg-final { only_for_offload_target amdgcn-amdhsa scan-offload-tree-dump "= gfx10_3_generic \\(\\);" "optimized" } } */

libgomp/testsuite/libgomp.c/declare-variant-4-gfx11-generic.c

@@ -0,0 +1,8 @@
+/* { dg-do link { target { offload_target_amdgcn } } } */
+/* { dg-additional-options -foffload=amdgcn-amdhsa } */
+/* { dg-additional-options -foffload=-march=gfx11-generic } */
+/* { dg-additional-options "-foffload=-fdump-tree-optimized" } */
+
+#include "declare-variant-4.h"
+
+/* { dg-final { only_for_offload_target amdgcn-amdhsa scan-offload-tree-dump "= gfx11_generic \\(\\);" "optimized" } } */

libgomp/testsuite/libgomp.c/declare-variant-4-gfx9-4-generic.c

@@ -0,0 +1,8 @@
+/* { dg-do link { target { offload_target_amdgcn } } } */
+/* { dg-additional-options -foffload=amdgcn-amdhsa } */
+/* { dg-additional-options -foffload=-march=gfx9-4-generic } */
+/* { dg-additional-options "-foffload=-fdump-tree-optimized" } */
+
+#include "declare-variant-4.h"
+
+/* { dg-final { only_for_offload_target amdgcn-amdhsa scan-offload-tree-dump "= gfx9_4_generic \\(\\);" "optimized" } } */

libgomp/testsuite/libgomp.c/declare-variant-4-gfx9-generic.c

@@ -0,0 +1,8 @@
+/* { dg-do link { target { offload_target_amdgcn } } } */
+/* { dg-additional-options -foffload=amdgcn-amdhsa } */
+/* { dg-additional-options -foffload=-march=gfx9-generic } */
+/* { dg-additional-options "-foffload=-fdump-tree-optimized" } */
+
+#include "declare-variant-4.h"
+
+/* { dg-final { only_for_offload_target amdgcn-amdhsa scan-offload-tree-dump "= gfx9_generic \\(\\);" "optimized" } } */

libgomp/testsuite/libgomp.c/declare-variant-4.h

@@ -7,6 +7,20 @@ gfx900 (void)
   return 0x900;
 }
 
+__attribute__ ((noipa))
+int
+gfx902 (void)
+{
+  return 0x902;
+}
+
+__attribute__ ((noipa))
+int
+gfx904 (void)
+{
+  return 0x904;
+}
+
 __attribute__ ((noipa))
 int
 gfx906 (void)
@@ -21,6 +35,13 @@ gfx908 (void)
   return 0x908;
 }
 
+__attribute__ ((noipa))
+int
+gfx909 (void)
+{
+  return 0x909;
+}
+
 __attribute__ ((noipa))
 int
 gfx90a (void)
@@ -42,6 +63,13 @@ gfx942 (void)
   return 0x942;
 }
 
+__attribute__ ((noipa))
+int
+gfx950 (void)
+{
+  return 0x950;
+}
+
 __attribute__ ((noipa))
 int
 gfx1030 (void)
@@ -49,6 +77,41 @@ gfx1030 (void)
   return 0x1030;
 }
 
+__attribute__ ((noipa))
+int
+gfx1031 (void)
+{
+  return 0x1031;
+}
+
+__attribute__ ((noipa))
+int
+gfx1032 (void)
+{
+  return 0x1032;
+}
+
+__attribute__ ((noipa))
+int
+gfx1033 (void)
+{
+  return 0x1033;
+}
+
+__attribute__ ((noipa))
+int
+gfx1034 (void)
+{
+  return 0x1034;
+}
+
+__attribute__ ((noipa))
+int
+gfx1035 (void)
+{
+  return 0x1035;
+}
+
 __attribute__ ((noipa))
 int
 gfx1036 (void)
@@ -63,6 +126,20 @@ gfx1100 (void)
   return 0x1100;
 }
 
+__attribute__ ((noipa))
+int
+gfx1101 (void)
+{
+  return 0x1101;
+}
+
+__attribute__ ((noipa))
+int
+gfx1102 (void)
+{
+  return 0x1102;
+}
+
 __attribute__ ((noipa))
 int
 gfx1103 (void)
@@ -70,16 +147,92 @@ gfx1103 (void)
   return 0x1103;
 }
 
+__attribute__ ((noipa))
+int
+gfx1150 (void)
+{
+  return 0x1150;
+}
+
+__attribute__ ((noipa))
+int
+gfx1151 (void)
+{
+  return 0x1151;
+}
+
+__attribute__ ((noipa))
+int
+gfx1152 (void)
+{
+  return 0x1152;
+}
+
+__attribute__ ((noipa))
+int
+gfx1153 (void)
+{
+  return 0x1153;
+}
+
+__attribute__ ((noipa))
+int
+gfx9_generic (void)
+{
+  return 0x90ff;
+}
+
+__attribute__ ((noipa))
+int
+gfx9_4_generic (void)
+{
+  return 0x94ff;
+}
+
+__attribute__ ((noipa))
+int
+gfx10_3_generic (void)
+{
+  return 0x103ff;
+}
+
+__attribute__ ((noipa))
+int
+gfx11_generic (void)
+{
+  return 0x110ff;
+}
+
+
 #pragma omp declare variant(gfx900) match(device = {isa("gfx900")})
+#pragma omp declare variant(gfx902) match(device = {isa("gfx902")})
+#pragma omp declare variant(gfx904) match(device = {isa("gfx904")})
 #pragma omp declare variant(gfx906) match(device = {isa("gfx906")})
 #pragma omp declare variant(gfx908) match(device = {isa("gfx908")})
+#pragma omp declare variant(gfx909) match(device = {isa("gfx909")})
 #pragma omp declare variant(gfx90a) match(device = {isa("gfx90a")})
 #pragma omp declare variant(gfx90c) match(device = {isa("gfx90c")})
 #pragma omp declare variant(gfx942) match(device = {isa("gfx942")})
+#pragma omp declare variant(gfx950) match(device = {isa("gfx950")})
 #pragma omp declare variant(gfx1030) match(device = {isa("gfx1030")})
+#pragma omp declare variant(gfx1031) match(device = {isa("gfx1031")})
+#pragma omp declare variant(gfx1032) match(device = {isa("gfx1032")})
+#pragma omp declare variant(gfx1033) match(device = {isa("gfx1033")})
+#pragma omp declare variant(gfx1034) match(device = {isa("gfx1034")})
+#pragma omp declare variant(gfx1035) match(device = {isa("gfx1035")})
 #pragma omp declare variant(gfx1036) match(device = {isa("gfx1036")})
 #pragma omp declare variant(gfx1100) match(device = {isa("gfx1100")})
+#pragma omp declare variant(gfx1101) match(device = {isa("gfx1101")})
+#pragma omp declare variant(gfx1102) match(device = {isa("gfx1102")})
 #pragma omp declare variant(gfx1103) match(device = {isa("gfx1103")})
+#pragma omp declare variant(gfx1150) match(device = {isa("gfx1150")})
+#pragma omp declare variant(gfx1151) match(device = {isa("gfx1151")})
+#pragma omp declare variant(gfx1152) match(device = {isa("gfx1152")})
+#pragma omp declare variant(gfx1153) match(device = {isa("gfx1153")})
+#pragma omp declare variant(gfx9_generic) match(device = {isa("gfx9-generic")})
+#pragma omp declare variant(gfx9_4_generic) match(device = {isa("gfx9-4-generic")})
+#pragma omp declare variant(gfx10_3_generic) match(device = {isa("gfx10-3-generic")})
+#pragma omp declare variant(gfx11_generic) match(device = {isa("gfx11-generic")})
 __attribute__ ((noipa))
 int
 f (void)