ac: set no-signed-zeros-fp-math when RADV_DEBUG="unsafemath" is used

This is an optimisation that is recommended by Matt Arsenault,
and used by RadeonSI, but it's not compatible with Vulkan.

Note that AC_FLOAT_MODE_UNSAFE_FP_MATH includes the no signed
zeros flag in LLVM.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
index 635a74d..5a8ddf1 100644 (file)
--- a/src/amd/common/ac_nir_to_llvm.c
+++ b/src/amd/common/ac_nir_to_llvm.c
@@ -352,6 +352,9 @@ create_llvm_function(LLVMContextRef ctx, LLVMModuleRef module,
                LLVMAddTargetDependentFunctionAttr(main_function,
                                                   "unsafe-fp-math",
                                                   "true");
+               LLVMAddTargetDependentFunctionAttr(main_function,
+                                          "no-signed-zeros-fp-math",
+                                          "true");
        }
        return main_function;
 }