R600_DEBUG=gisel will tell LLVM to use GlobalISel rather than
SelectionDAG for instruction selection.
---
src/amd/common/ac_llvm_util.c | 14 ++++++++++++--
src/amd/common/ac_llvm_util.h | 1 +
src/gallium/auxiliary/gallivm/lp_bld_misc.cpp | 7 +++++++
src/gallium/auxiliary/gallivm/lp_bld_misc.h | 3 +++
src/gallium/drivers/radeonsi/si_pipe.c | 3 +++
src/gallium/drivers/radeonsi/si_pipe.h | 1 +
6 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/src/amd/common/ac_llvm_util.c b/src/amd/common/ac_llvm_util.c
index be2d92b4c0..7e211950e0 100644
--- a/src/amd/common/ac_llvm_util.c
+++ b/src/amd/common/ac_llvm_util.c
@@ -29,6 +29,7 @@
#include <llvm-c/Core.h>
#include <llvm-c/Support.h>
#include "c11/threads.h"
+#include "gallivm/lp_bld_misc.h"
#include "util/u_math.h"
#include <assert.h>
@@ -50,9 +51,13 @@ static void ac_init_llvm_target()
* https://reviews.llvm.org/D26348
*
* "mesa" is the prefix for error messages.
+ *
+ * -global-isel-abort=2 is a no-op unless global isel has been enabled.
+ * This option tells the backend to fall-back to SelectionDAG and print
+ * a diagnostic message if global isel fails.
*/
- const char *argv[2] = { "mesa", "-simplifycfg-sink-common=false" };
- LLVMParseCommandLineOptions(2, argv, NULL);
+ const char *argv[3] = { "mesa", "-simplifycfg-sink-common=false",
"-global-isel-abort=2" };
+ LLVMParseCommandLineOptions(3, argv, NULL);
}
static once_flag ac_init_llvm_target_once_flag = ONCE_FLAG_INIT;
@@ -152,6 +157,11 @@ LLVMTargetMachineRef ac_create_target_machine(enum
radeon_family family,
if (out_triple)
*out_triple = triple;
+
+ if (tm_options & AC_TM_ENABLE_GLOBAL_ISEL) {
+ lp_enable_global_isel(tm);
+ }
+
return tm;
}
diff --git a/src/amd/common/ac_llvm_util.h b/src/amd/common/ac_llvm_util.h
index 0aa803c5bc..31d7c4e4ff 100644
--- a/src/amd/common/ac_llvm_util.h
+++ b/src/amd/common/ac_llvm_util.h
@@ -59,6 +59,7 @@ enum ac_target_machine_options {
AC_TM_FORCE_ENABLE_XNACK = (1 << 2),
AC_TM_FORCE_DISABLE_XNACK = (1 << 3),
AC_TM_PROMOTE_ALLOCA_TO_SCRATCH = (1 << 4),
+ AC_TM_ENABLE_GLOBAL_ISEL = (1 << 5)
};
enum ac_float_mode {
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
index 79dbedbb56..ca8d4fb24c 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
+++ b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
@@ -813,3 +813,10 @@ lp_is_function(LLVMValueRef v)
return llvm::isa<llvm::Function>(llvm::unwrap(v));
#endif
}
+
+extern "C" void lp_enable_global_isel(LLVMTargetMachineRef tm)
+{
+#if HAVE_LLVM >= 0x0700
+ reinterpret_cast<llvm::TargetMachine*>(tm)->setGlobalISel(true);
+#endif
+}
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_misc.h
b/src/gallium/auxiliary/gallivm/lp_bld_misc.h
index ca5ba5c44f..187dbc46c9 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_misc.h
+++ b/src/gallium/auxiliary/gallivm/lp_bld_misc.h
@@ -76,6 +76,9 @@ lp_get_called_value(LLVMValueRef call);
extern bool
lp_is_function(LLVMValueRef v);
+extern void
+lp_enable_global_isel(LLVMTargetMachineRef tm);
+
#ifdef __cplusplus
}
#endif
diff --git a/src/gallium/drivers/radeonsi/si_pipe.c
b/src/gallium/drivers/radeonsi/si_pipe.c
index ded8cb5eb0..61c34b3e0c 100644
--- a/src/gallium/drivers/radeonsi/si_pipe.c
+++ b/src/gallium/drivers/radeonsi/si_pipe.c
@@ -63,6 +63,7 @@ static const struct debug_named_value debug_options[] = {
/* Shader compiler options the shader cache should be aware of: */
{ "unsafemath", DBG(UNSAFE_MATH), "Enable unsafe math shader
optimizations" },
{ "sisched", DBG(SI_SCHED), "Enable LLVM SI Machine Instruction
Scheduler." },
+ { "gisel", DBG(GISEL), "Enable LLVM global instruction selector." },
/* Shader compiler options (with no effect on the shader cache): */
{ "checkir", DBG(CHECK_IR), "Enable additional sanity checks on shader
IR" },
@@ -115,6 +116,7 @@ static void si_init_compiler(struct si_screen *sscreen,
{
enum ac_target_machine_options tm_options =
(sscreen->debug_flags & DBG(SI_SCHED) ? AC_TM_SISCHED : 0) |
+ (sscreen->debug_flags & DBG(GISEL) ? AC_TM_ENABLE_GLOBAL_ISEL :
0) |
(sscreen->info.chip_class >= GFX9 ? AC_TM_FORCE_ENABLE_XNACK :
0) |
(sscreen->info.chip_class < GFX9 ? AC_TM_FORCE_DISABLE_XNACK :
0) |
(!sscreen->llvm_has_working_vgpr_indexing ?
AC_TM_PROMOTE_ALLOCA_TO_SCRATCH : 0);
@@ -805,6 +807,7 @@ static void si_disk_cache_create(struct si_screen *sscreen)
/* These flags affect shader compilation. */
#define ALL_FLAGS (DBG(FS_CORRECT_DERIVS_AFTER_KILL) | \
DBG(SI_SCHED) | \
+ DBG(GISEL) | \
DBG(UNSAFE_MATH) | \
DBG(NIR))
uint64_t shader_debug_flags = sscreen->debug_flags &
diff --git a/src/gallium/drivers/radeonsi/si_pipe.h
b/src/gallium/drivers/radeonsi/si_pipe.h
index bd857f8a34..6dd66617af 100644
--- a/src/gallium/drivers/radeonsi/si_pipe.h
+++ b/src/gallium/drivers/radeonsi/si_pipe.h
@@ -121,6 +121,7 @@ enum {
DBG_FS_CORRECT_DERIVS_AFTER_KILL,
DBG_UNSAFE_MATH,
DBG_SI_SCHED,
+ DBG_GISEL,
/* Shader compiler options (with no effect on the shader cache): */
DBG_CHECK_IR,
--
2.17.0
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