https://gcc.gnu.org/g:b31fa1ce19542e14bea10f46240f39cb37277b80
commit r16-2637-gb31fa1ce19542e14bea10f46240f39cb37277b80
Author: Andrew Stubbs <a...@baylibre.com>
Date: Thu Jul 24 12:58:31 2025 +0000
Don't pass vector params through to offload targets
The optimization options are deliberately passed through to the LTO
compiler,
but when the same mechanism is reused for offloading it ends up forcing the
host compiler settings onto the device compiler. Maybe this should be
removed
completely, but this patch just fixes a few of them. In particular,
param_vect_partial_vector_usage is disabled by x86 and this really hurts
amdgcn.
I also fixed an ambiguous else warning in the generated file by adding
braces.
gcc/ChangeLog:
* config/gcn/gcn.cc (gcn_option_override): Add note to set default
for
param_vect_partial_vector_usage to "1".
* optc-save-gen.awk: Don't pass through options marked "NoOffload".
* params.opt (-param=vect-epilogues-nomask): Add NoOffload.
(-param=vect-partial-vector-usage): Likewise.
(-param=vect-inner-loop-cost-factor): Likewise.
Diff:
---
gcc/config/gcn/gcn.cc | 6 ++++++
gcc/optc-save-gen.awk | 19 +++++++++++++++++--
gcc/params.opt | 6 +++---
3 files changed, 26 insertions(+), 5 deletions(-)
diff --git a/gcc/config/gcn/gcn.cc b/gcc/config/gcn/gcn.cc
index 557568c38c33..803ffa791d5e 100644
--- a/gcc/config/gcn/gcn.cc
+++ b/gcc/config/gcn/gcn.cc
@@ -54,6 +54,7 @@
#include "gimple.h"
#include "cgraph.h"
#include "case-cfn-macros.h"
+#include "opts.h"
/* This file should be included last. */
#include "target-def.h"
@@ -183,6 +184,11 @@ gcn_option_override (void)
if (flag_sram_ecc == HSACO_ATTR_DEFAULT)
flag_sram_ecc = gcn_devices[gcn_arch].sramecc_default;
+
+ /* TODO: This seems to produce tighter loops, but the testsuites expects it
+ to be set to '2', so I'll leave it default for now.
+ SET_OPTION_IF_UNSET (&global_options, &global_options_set,
+ param_vect_partial_vector_usage, 1); */
}
/* }}} */
diff --git a/gcc/optc-save-gen.awk b/gcc/optc-save-gen.awk
index a3d7e5a478e4..31756ec380d2 100644
--- a/gcc/optc-save-gen.awk
+++ b/gcc/optc-save-gen.awk
@@ -1313,6 +1313,12 @@ for (i = 0; i < n_opts; i++) {
# offloading is enabled.
if (flag_set_p("Target", flags[i]))
var_target_opt[n_opt_val] = 1;
+
+ # These options should not be passed from host to target, but
+ # are not actually target specific.
+ if (flag_set_p("NoOffload", flags[i]))
+ var_target_opt[n_opt_val] = 2;
+
n_opt_val++;
}
}
@@ -1393,7 +1399,7 @@ for (i = 0; i < n_opt_val; i++) {
# Do not stream out target-specific opts if offloading is
# enabled.
if (var_target_opt[i])
- print " if (!lto_stream_offload_p)"
+ print " if (!lto_stream_offload_p) {"
# If applicable, encode the streamed value.
if (var_opt_optimize_init[i]) {
print " if (" var_opt_optimize_init[i] " > ("
var_opt_val_type[i] ") 10)";
@@ -1403,6 +1409,8 @@ for (i = 0; i < n_opt_val; i++) {
} else {
print " bp_pack_var_len_" sgn " (bp, ptr->" name");";
}
+ if (var_target_opt[i])
+ print "}"
}
}
print " for (size_t i = 0; i < ARRAY_SIZE (ptr->explicit_mask); i++)";
@@ -1418,10 +1426,14 @@ print " struct
cl_optimization *ptr ATTRIBUTE_UNUSED)"
print "{";
for (i = 0; i < n_opt_val; i++) {
name = var_opt_val[i]
- if (var_target_opt[i]) {
+ if (var_target_opt[i] == 1) {
print "#ifdef ACCEL_COMPILER"
print "#error accel compiler cannot define Optimization
attribute for target-specific option " name;
print "#else"
+ } else if (var_target_opt[i] == 2) {
+ print "#ifdef ACCEL_COMPILER"
+ print " ptr->" name " = global_options." name ";"
+ print "#else"
}
otype = var_opt_val_type[i];
if (otype ~ "^const char \\**$") {
@@ -1489,6 +1501,9 @@ for (i = 0; i < n_opts; i++) {
if (flag_set_p("Warning", flags[i]))
continue;
+ if (flag_set_p("NoOffload", flags[i]))
+ continue;
+
if (name in checked_options)
continue;
checked_options[name]++
diff --git a/gcc/params.opt b/gcc/params.opt
index c7d5fd4d13bd..ac1b2c7eb262 100644
--- a/gcc/params.opt
+++ b/gcc/params.opt
@@ -1226,7 +1226,7 @@ Common Joined UInteger Var(param_use_canonical_types)
Init(1) IntegerRange(0, 1)
Whether to use canonical types.
-param=vect-epilogues-nomask=
-Common Joined UInteger Var(param_vect_epilogues_nomask) Init(1)
IntegerRange(0, 1) Param Optimization
+Common Joined UInteger Var(param_vect_epilogues_nomask) Init(1)
IntegerRange(0, 1) Param Optimization NoOffload
Enable loop epilogue vectorization using smaller vector size.
-param=vect-max-layout-candidates=
@@ -1246,11 +1246,11 @@ Common Joined UInteger
Var(param_vect_max_version_for_alignment_checks) Init(6)
Bound on number of runtime checks inserted by the vectorizer's loop versioning
for alignment check.
-param=vect-partial-vector-usage=
-Common Joined UInteger Var(param_vect_partial_vector_usage) Init(2)
IntegerRange(0, 2) Param Optimization
+Common Joined UInteger Var(param_vect_partial_vector_usage) Init(2)
IntegerRange(0, 2) Param Optimization NoOffload
Controls how loop vectorizer uses partial vectors. 0 means never, 1 means
only for loops whose need to iterate can be removed, 2 means for all loops.
The default value is 2.
-param=vect-inner-loop-cost-factor=
-Common Joined UInteger Var(param_vect_inner_loop_cost_factor) Init(50)
IntegerRange(1, 10000) Param Optimization
+Common Joined UInteger Var(param_vect_inner_loop_cost_factor) Init(50)
IntegerRange(1, 10000) Param Optimization NoOffload
The maximum factor which the loop vectorizer applies to the cost of statements
in an inner loop relative to the loop being vectorized.
-param=vect-induction-float=
