radv: add a workaround for Monster Hunter World and LLVM 7&8

The load/store optimizer pass doesn't handle WaW hazards correctly
and this is the root cause of the reflection issue with Monster
Hunter World. AFAIK, it's the only game that are affected by this
issue.

This is fixed with LLVM r361008, but we need a workaround for older
LLVM versions unfortunately.

Cc: "19.0" "19.1" <[email protected]>
Signed-off-by: Samuel Pitoiset <[email protected]>
Reviewed-by: Bas Nieuwenhuizen <[email protected]>

5 files changed, 16 insertions, 3 deletions

diff --git a/src/amd/common/ac_llvm_util.c b/src/amd/common/ac_llvm_util.c
index 69446863b95..6063411310b 100644
--- a/src/amd/common/ac_llvm_util.c
+++ b/src/amd/common/ac_llvm_util.c
@@ -151,13 +151,14 @@ static LLVMTargetMachineRef ac_create_target_machine(enum radeon_family family,
 	LLVMTargetRef target = ac_get_llvm_target(triple);
 
 	snprintf(features, sizeof(features),
-		 "+DumpCode,-fp32-denormals,+fp64-denormals%s%s%s%s%s",
+		 "+DumpCode,-fp32-denormals,+fp64-denormals%s%s%s%s%s%s",
 		 HAVE_LLVM >= 0x0800 ? "" : ",+vgpr-spilling",
 		 tm_options & AC_TM_SISCHED ? ",+si-scheduler" : "",
 		 tm_options & AC_TM_FORCE_ENABLE_XNACK ? ",+xnack" : "",
 		 tm_options & AC_TM_FORCE_DISABLE_XNACK ? ",-xnack" : "",
-		 tm_options & AC_TM_PROMOTE_ALLOCA_TO_SCRATCH ? ",-promote-alloca" : "");
-	
+		 tm_options & AC_TM_PROMOTE_ALLOCA_TO_SCRATCH ? ",-promote-alloca" : "",
+		 tm_options & AC_TM_NO_LOAD_STORE_OPT ? ",-load-store-opt" : "");
+
 	LLVMTargetMachineRef tm = LLVMCreateTargetMachine(
 	                             target,
 	                             triple,
diff --git a/src/amd/common/ac_llvm_util.h b/src/amd/common/ac_llvm_util.h
index 6d961c06f8a..ca00540da80 100644
--- a/src/amd/common/ac_llvm_util.h
+++ b/src/amd/common/ac_llvm_util.h
@@ -65,6 +65,7 @@ enum ac_target_machine_options {
 	AC_TM_CHECK_IR = (1 << 5),
 	AC_TM_ENABLE_GLOBAL_ISEL = (1 << 6),
 	AC_TM_CREATE_LOW_OPT = (1 << 7),
+	AC_TM_NO_LOAD_STORE_OPT = (1 << 8),
 };
 
 enum ac_float_mode {
diff --git a/src/amd/vulkan/radv_debug.h b/src/amd/vulkan/radv_debug.h
index 17a2f3370c0..652a3b677d2 100644
--- a/src/amd/vulkan/radv_debug.h
+++ b/src/amd/vulkan/radv_debug.h
@@ -51,6 +51,7 @@ enum {
 	RADV_DEBUG_CHECKIR           = 0x200000,
 	RADV_DEBUG_NOTHREADLLVM      = 0x400000,
 	RADV_DEBUG_NOBINNING         = 0x800000,
+	RADV_DEBUG_NO_LOAD_STORE_OPT = 0x1000000,
 };
 
 enum {
diff --git a/src/amd/vulkan/radv_device.c b/src/amd/vulkan/radv_device.c
index c0e317a97e5..4203074a4cd 100644
--- a/src/amd/vulkan/radv_device.c
+++ b/src/amd/vulkan/radv_device.c
@@ -464,6 +464,7 @@ static const struct debug_control radv_debug_options[] = {
 	{"checkir", RADV_DEBUG_CHECKIR},
 	{"nothreadllvm", RADV_DEBUG_NOTHREADLLVM},
 	{"nobinning", RADV_DEBUG_NOBINNING},
+	{"noloadstoreopt", RADV_DEBUG_NO_LOAD_STORE_OPT},
 	{NULL, 0}
 };
 
@@ -510,6 +511,13 @@ radv_handle_per_app_options(struct radv_instance *instance,
 	} else if (!strcmp(name, "DOOM_VFR")) {
 		/* Work around a Doom VFR game bug */
 		instance->debug_flags |= RADV_DEBUG_NO_DYNAMIC_BOUNDS;
+	} else if (!strcmp(name, "MonsterHunterWorld.exe")) {
+		/* Workaround for a WaW hazard when LLVM moves/merges
+		 * load/store memory operations.
+		 * See https://reviews.llvm.org/D61313
+		 */
+		if (HAVE_LLVM < 0x900)
+			instance->debug_flags |= RADV_DEBUG_NO_LOAD_STORE_OPT;
 	}
 }
 
diff --git a/src/amd/vulkan/radv_shader.c b/src/amd/vulkan/radv_shader.c
index dfa50155c06..c585bac860f 100644
--- a/src/amd/vulkan/radv_shader.c
+++ b/src/amd/vulkan/radv_shader.c
@@ -649,6 +649,8 @@ shader_variant_create(struct radv_device *device,
 		tm_options |= AC_TM_SISCHED;
 	if (options->check_ir)
 		tm_options |= AC_TM_CHECK_IR;
+	if (device->instance->debug_flags & RADV_DEBUG_NO_LOAD_STORE_OPT)
+		tm_options |= AC_TM_NO_LOAD_STORE_OPT;
 
 	thread_compiler = !(device->instance->debug_flags & RADV_DEBUG_NOTHREADLLVM);
 	radv_init_llvm_once();