radv: disable the auto-waitcnt-before-barrier LLVM option

This option allows us to remove additional s_waitcnt instructions
because s_barrier internally does s_waitcnt 0.

Though, apparently there is a problem with LDS accesses that
causes rendering issues with FFXV and DXVK. Disable this
optimization for now (RadeonSI still uses it).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107460
CC: 18.2 <mesa-stable@lists.freedesktop.org>
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

diff --git a/src/amd/common/ac_llvm_util.c b/src/amd/common/ac_llvm_util.c
index 10e1ca99d41f2b13219ef589097aa0ca09c79cb2..42bc538b4d75e58c60b72fd5fa473f6fdfe43e38 100644 (file)
--- a/src/amd/common/ac_llvm_util.c
+++ b/src/amd/common/ac_llvm_util.c
@@ -149,7 +149,8 @@ static LLVMTargetMachineRef ac_create_target_machine(enum radeon_family family,
        char features[256];
        const char *triple = (tm_options & AC_TM_SUPPORTS_SPILL) ? "amdgcn-mesa-mesa3d" : "amdgcn--";
        LLVMTargetRef target = ac_get_llvm_target(triple);
-       bool barrier_does_waitcnt = family != CHIP_VEGA20;
+       bool barrier_does_waitcnt = (tm_options & AC_TM_AUTO_WAITCNT_BEFORE_BARRIER) &&
+                                   family != CHIP_VEGA20;
 
        snprintf(features, sizeof(features),
                 "+DumpCode,+vgpr-spilling,-fp32-denormals,+fp64-denormals%s%s%s%s%s",

diff --git a/src/amd/common/ac_llvm_util.h b/src/amd/common/ac_llvm_util.h
index eaf5f21876b99b610765566fff28b4f4500713db..e252bed3bb676a6fe37c8124046a58063dfd9c9d 100644 (file)
--- 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_AUTO_WAITCNT_BEFORE_BARRIER = (1 << 8),
 };
 
 enum ac_float_mode {

diff --git a/src/gallium/drivers/radeonsi/si_pipe.c b/src/gallium/drivers/radeonsi/si_pipe.c
index 13fcf1f3aeaac27e94f187a989854839f1cf6d85..4327a3f749b1bc19c60039fee9f480c2d7683869 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_pipe.c
+++ b/src/gallium/drivers/radeonsi/si_pipe.c
@@ -115,6 +115,7 @@ static void si_init_compiler(struct si_screen *sscreen,
                                       sscreen->info.chip_class <= VI;
 
        enum ac_target_machine_options tm_options =
+               AC_TM_AUTO_WAITCNT_BEFORE_BARRIER |
                (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) |