[gcc r12-7098] [nvptx] Choose -mptx default based on -misa
Tom de Vries
vries@gcc.gnu.org
Tue Feb 8 12:57:13 GMT 2022
https://gcc.gnu.org/g:decde11183bdccc46587d6614b75f3d56a2f2e4a
commit r12-7098-gdecde11183bdccc46587d6614b75f3d56a2f2e4a
Author: Tom de Vries <tdevries@suse.de>
Date: Fri Feb 4 08:53:52 2022 +0100
[nvptx] Choose -mptx default based on -misa
While testing with driver version 390.147 I ran into the problem that it
doesn't support ptx isa version 6.3 (the new default), only 6.1.
Furthermore, using the -mptx option is a bit user-unfriendly.
Say we want to compile for sm_80. We can use -misa=sm_80 to specify that, but
then run into errors because the default ptx version is 6.3, which doesn't
support sm_80 yet.
Address both these issues by:
- picking a default -mptx based on the active -misa, and
- ensuring that the default -mptx is at least 6.0 (instead
of 6.3).
Also add an error in case of incompatible options like
"-misa=sm_80 -mptx=6.3":
...
cc1: error: PTX version (-mptx) needs to be at least 7.0 to support \
selected -misa (sm_80)
...
Tested on x86_64-linux with nvptx accelerator.
gcc/ChangeLog:
2022-02-08 Tom de Vries <tdevries@suse.de>
PR target/104283
* config/nvptx/nvptx-opts.h (enum ptx_version): Add PTX_VERSION_3_0
and PTX_VERSION_4_2.
* config/nvptx/nvptx.cc (first_ptx_version_supporting_sm)
(default_ptx_version_option, ptx_version_to_string)
(sm_version_to_string, handle_ptx_version_option): New function.
(nvptx_option_override): Call handle_ptx_version_option.
(nvptx_file_start): Use ptx_version_to_string and sm_version_to_string.
* config/nvptx/nvptx.md (define_insn "nvptx_shuffle<mode>")
(define_insn "nvptx_vote_ballot"): Use TARGET_PTX_6_0.
* config/nvptx/nvptx.opt (mptx): Remove 'Init'.
Diff:
---
gcc/config/nvptx/nvptx-opts.h | 2 +
gcc/config/nvptx/nvptx.cc | 133 +++++++++++++++++++++++++++++++++++++-----
gcc/config/nvptx/nvptx.md | 4 +-
gcc/config/nvptx/nvptx.opt | 2 +-
4 files changed, 122 insertions(+), 19 deletions(-)
diff --git a/gcc/config/nvptx/nvptx-opts.h b/gcc/config/nvptx/nvptx-opts.h
index c754a5193ce..cc488b23720 100644
--- a/gcc/config/nvptx/nvptx-opts.h
+++ b/gcc/config/nvptx/nvptx-opts.h
@@ -31,7 +31,9 @@ enum ptx_isa
enum ptx_version
{
+ PTX_VERSION_3_0,
PTX_VERSION_3_1,
+ PTX_VERSION_4_2,
PTX_VERSION_6_0,
PTX_VERSION_6_3,
PTX_VERSION_7_0
diff --git a/gcc/config/nvptx/nvptx.cc b/gcc/config/nvptx/nvptx.cc
index 006fac8c839..1b0227a2c31 100644
--- a/gcc/config/nvptx/nvptx.cc
+++ b/gcc/config/nvptx/nvptx.cc
@@ -205,6 +205,109 @@ diagnose_openacc_conflict (bool optval, const char *optname)
error ("option %s is not supported together with %<-fopenacc%>", optname);
}
+static enum ptx_version
+first_ptx_version_supporting_sm (enum ptx_isa sm)
+{
+ switch (sm)
+ {
+ case PTX_ISA_SM30:
+ return PTX_VERSION_3_0;
+ case PTX_ISA_SM35:
+ return PTX_VERSION_3_1;
+ case PTX_ISA_SM53:
+ return PTX_VERSION_4_2;
+ case PTX_ISA_SM75:
+ return PTX_VERSION_6_3;
+ case PTX_ISA_SM80:
+ return PTX_VERSION_7_0;
+ default:
+ gcc_unreachable ();
+ }
+}
+
+static enum ptx_version
+default_ptx_version_option (void)
+{
+ enum ptx_version first
+ = first_ptx_version_supporting_sm ((enum ptx_isa) ptx_isa_option);
+
+ /* Pick a version that supports the sm. */
+ enum ptx_version res = first;
+
+ /* Pick at least 3.1. This has been the smallest version historically. */
+ res = MAX (res, PTX_VERSION_3_1);
+
+ /* Pick at least 6.0, to enable using bar.warp.sync to have a way to force
+ warp convergence. */
+ res = MAX (res, PTX_VERSION_6_0);
+
+ /* Verify that we pick a version that supports the sm. */
+ gcc_assert (first <= res);
+ return res;
+}
+
+static const char *
+ptx_version_to_string (enum ptx_version v)
+{
+ switch (v)
+ {
+ case PTX_VERSION_3_0:
+ return "3.0";
+ case PTX_VERSION_3_1:
+ return "3.1";
+ case PTX_VERSION_4_2:
+ return "4.2";
+ case PTX_VERSION_6_0:
+ return "6.0";
+ case PTX_VERSION_6_3:
+ return "6.3";
+ case PTX_VERSION_7_0:
+ return "7.0";
+ default:
+ gcc_unreachable ();
+ }
+}
+
+static const char *
+sm_version_to_string (enum ptx_isa sm)
+{
+ switch (sm)
+ {
+ case PTX_ISA_SM30:
+ return "30";
+ case PTX_ISA_SM35:
+ return "35";
+ case PTX_ISA_SM53:
+ return "53";
+ case PTX_ISA_SM70:
+ return "70";
+ case PTX_ISA_SM75:
+ return "75";
+ case PTX_ISA_SM80:
+ return "80";
+ default:
+ gcc_unreachable ();
+ }
+}
+
+static void
+handle_ptx_version_option (void)
+{
+ if (!OPTION_SET_P (ptx_version_option))
+ {
+ ptx_version_option = default_ptx_version_option ();
+ return;
+ }
+
+ enum ptx_version first
+ = first_ptx_version_supporting_sm ((enum ptx_isa) ptx_isa_option);
+
+ if (ptx_version_option < first)
+ error ("PTX version (-mptx) needs to be at least %s to support selected"
+ " -misa (sm_%s)", ptx_version_to_string (first),
+ sm_version_to_string ((enum ptx_isa)ptx_isa_option));
+}
+
/* Implement TARGET_OPTION_OVERRIDE. */
static void
@@ -212,6 +315,8 @@ nvptx_option_override (void)
{
init_machine_status = nvptx_init_machine_status;
+ handle_ptx_version_option ();
+
/* Set toplevel_reorder, unless explicitly disabled. We need
reordering so that we emit necessary assembler decls of
undeclared variables. */
@@ -5430,23 +5535,19 @@ static void
nvptx_file_start (void)
{
fputs ("// BEGIN PREAMBLE\n", asm_out_file);
- if (TARGET_PTX_7_0)
- fputs ("\t.version\t7.0\n", asm_out_file);
- else if (TARGET_PTX_6_3)
- fputs ("\t.version\t6.3\n", asm_out_file);
- else
- fputs ("\t.version\t3.1\n", asm_out_file);
- if (TARGET_SM80)
- fputs ("\t.target\tsm_80\n", asm_out_file);
- else if (TARGET_SM75)
- fputs ("\t.target\tsm_75\n", asm_out_file);
- else if (TARGET_SM53)
- fputs ("\t.target\tsm_53\n", asm_out_file);
- else if (TARGET_SM35)
- fputs ("\t.target\tsm_35\n", asm_out_file);
- else
- fputs ("\t.target\tsm_30\n", asm_out_file);
+
+ fputs ("\t.version\t", asm_out_file);
+ fputs (ptx_version_to_string ((enum ptx_version)ptx_version_option),
+ asm_out_file);
+ fputs ("\n", asm_out_file);
+
+ fputs ("\t.target\tsm_", asm_out_file);
+ fputs (sm_version_to_string ((enum ptx_isa)ptx_isa_option),
+ asm_out_file);
+ fputs ("\n", asm_out_file);
+
fprintf (asm_out_file, "\t.address_size %d\n", GET_MODE_BITSIZE (Pmode));
+
fputs ("// END PREAMBLE\n", asm_out_file);
}
diff --git a/gcc/config/nvptx/nvptx.md b/gcc/config/nvptx/nvptx.md
index d64dbfd8b33..7463603a0b0 100644
--- a/gcc/config/nvptx/nvptx.md
+++ b/gcc/config/nvptx/nvptx.md
@@ -1603,7 +1603,7 @@
UNSPEC_SHUFFLE))]
""
{
- if (TARGET_PTX_6_3)
+ if (TARGET_PTX_6_0)
return "%.\\tshfl.sync%S3.b32\\t%0, %1, %2, 31, 0xffffffff;";
else
return "%.\\tshfl%S3.b32\\t%0, %1, %2, 31;";
@@ -1615,7 +1615,7 @@
UNSPEC_VOTE_BALLOT))]
""
{
- if (TARGET_PTX_6_3)
+ if (TARGET_PTX_6_0)
return "%.\\tvote.sync.ballot.b32\\t%0, %1, 0xffffffff;";
else
return "%.\\tvote.ballot.b32\\t%0, %1;";
diff --git a/gcc/config/nvptx/nvptx.opt b/gcc/config/nvptx/nvptx.opt
index 6e12b1f7296..e3f65b2d0b1 100644
--- a/gcc/config/nvptx/nvptx.opt
+++ b/gcc/config/nvptx/nvptx.opt
@@ -89,5 +89,5 @@ EnumValue
Enum(ptx_version) String(7.0) Value(PTX_VERSION_7_0)
mptx=
-Target RejectNegative ToLower Joined Enum(ptx_version) Var(ptx_version_option) Init(PTX_VERSION_6_3)
+Target RejectNegative ToLower Joined Enum(ptx_version) Var(ptx_version_option)
Specify the version of the ptx version to use.
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