Add support for SPV_INTEL_fp_fast_math_mode (#822)

Spec: KhronosGroup/SPIRV-Registry#85

Signed-off-by: amochalo <anastasiya.mochalova@intel.com>

Author: MochalovaAn

llvm-spirv/include/LLVMSPIRVExtensions.inc

@@ -27,3 +27,4 @@ EXT(SPV_INTEL_fpga_buffer_location)
 EXT(SPV_INTEL_arbitrary_precision_fixed_point)
 EXT(SPV_INTEL_arbitrary_precision_floating_point)
 EXT(SPV_INTEL_variable_length_array)
+EXT(SPV_INTEL_fp_fast_math_mode)

llvm-spirv/lib/SPIRV/SPIRVReader.cpp

@@ -1127,6 +1127,10 @@ static void applyFPFastMathModeDecorations(const SPIRVValue *BV,
       FMF.setNoSignedZeros();
     if (V & FPFastMathModeAllowRecipMask)
       FMF.setAllowReciprocal();
+    if (V & FPFastMathModeAllowContractINTELMask)
+      FMF.setAllowContract();
+    if (V & FPFastMathModeAllowReassocINTELMask)
+      FMF.setAllowReassoc();
     if (V & FPFastMathModeFastMask)
       FMF.setFast();
     Inst->setFastMathFlags(FMF);

llvm-spirv/lib/SPIRV/SPIRVWriter.cpp

@@ -1706,6 +1706,17 @@ bool LLVMToSPIRV::transDecoration(Value *V, SPIRVValue *BV) {
           M |= FPFastMathModeNSZMask;
         if (FMF.allowReciprocal())
           M |= FPFastMathModeAllowRecipMask;
+        if (BM->isAllowedToUseExtension(
+                ExtensionID::SPV_INTEL_fp_fast_math_mode)) {
+          if (FMF.allowContract()) {
+            M |= FPFastMathModeAllowContractINTELMask;
+            BM->addCapability(CapabilityFPFastMathModeINTEL);
+          }
+          if (FMF.allowReassoc()) {
+            M |= FPFastMathModeAllowReassocINTELMask;
+            BM->addCapability(CapabilityFPFastMathModeINTEL);
+          }
+        }
       }
       if (M != 0)
         BV->setFPFastMathMode(M);

llvm-spirv/lib/SPIRV/libSPIRV/SPIRVNameMapEnum.h

@@ -488,6 +488,7 @@ template <> inline void SPIRVMap<Capability, std::string>::init() {
   add(CapabilityVariableLengthArrayINTEL, "VariableLengthArrayINTEL");
   add(CapabilityFunctionFloatControlINTEL, "FunctionFloatControlINTEL");
   add(CapabilityFPGAMemoryAttributesINTEL, "FPGAMemoryAttributesINTEL");
+  add(CapabilityFPFastMathModeINTEL, "FPFastMathModeINTEL");
   add(CapabilityArbitraryPrecisionIntegersINTEL,
       "ArbitraryPrecisionIntegersINTEL");
   add(CapabilityArbitraryPrecisionFloatingPointINTEL,

llvm-spirv/lib/SPIRV/libSPIRV/spirv.hpp

@@ -377,6 +377,8 @@ enum FPFastMathModeMask {
     FPFastMathModeNotInfMask = 0x00000002,
     FPFastMathModeNSZMask = 0x00000004,
     FPFastMathModeAllowRecipMask = 0x00000008,
+    FPFastMathModeAllowContractINTELMask = 0x00010000,
+    FPFastMathModeAllowReassocINTELMask = 0x00020000,
     FPFastMathModeFastMask = 0x00000010,
 };
 
@@ -975,6 +977,7 @@ enum Capability {
   CapabilityVariableLengthArrayINTEL = 5817,
   CapabilityFunctionFloatControlINTEL = 5821,
   CapabilityFPGAMemoryAttributesINTEL = 5824,
+  CapabilityFPFastMathModeINTEL = 5837,
   CapabilityArbitraryPrecisionIntegersINTEL = 5844,
   CapabilityArbitraryPrecisionFloatingPointINTEL = 5845,
   CapabilityUnstructuredLoopControlsINTEL = 5886,

llvm-spirv/test/transcoding/fp_contract_reassoc_fast_mode.ll

@@ -0,0 +1,56 @@
+; RUN: llvm-as %s -o %t.bc
+; RUN: llvm-spirv -spirv-text %t.bc -o - | FileCheck %s --check-prefix=CHECK-SPIRV-OFF
+; RUN: llvm-spirv --spirv-ext=+SPV_INTEL_fp_fast_math_mode -spirv-text %t.bc -o - | FileCheck %s --check-prefix=CHECK-SPIRV-ON
+; RUN: llvm-spirv  --spirv-ext=+SPV_INTEL_fp_fast_math_mode %t.bc -o %t.spv
+; RUN: llvm-spirv -r %t.spv -o - | llvm-dis -o - | FileCheck %s --check-prefix=CHECK-LLVM
+ 
+; CHECK-SPIRV-ON: 2 Capability FPFastMathModeINTEL
+; CHECK-SPIRV-ON: 3 Name [[mu:[0-9]+]] "mul"
+; CHECK-SPIRV-ON: 3 Name [[su:[0-9]+]] "sub"
+; CHECK-SPIRV-ON: 4 Decorate [[mu]] FPFastMathMode 65536
+; CHECK-SPIRV-ON: 4 Decorate [[su]] FPFastMathMode 131072
+
+; CHECK-SPIRV-OFF-NOT: 2 Capability FPFastMathModeINTEL
+; CHECK-SPIRV-OFF: 3 Name [[mu:[0-9]+]] "mul"
+; CHECK-SPIRV-OFF: 3 Name [[su:[0-9]+]] "sub"
+; CHECK-SPIRV-OFF-NOT: 4 Decorate [[mu]] FPFastMathMode 65536
+; CHECK-SPIRV-OFF-NOT: 4 Decorate [[su]] FPFastMathMode 131072
+
+; CHECK-LLVM: %mul = fmul contract float %0, %1
+; CHECK-LLVM: %sub = fsub reassoc float %2, %3
+
+target datalayout = "e-p:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-n8:16:32:64"
+target triple = "spir"
+
+; Function Attrs: convergent noinline norecurse nounwind optnone
+define spir_kernel void @test(float %a, float %b) #0 !kernel_arg_addr_space !3 !kernel_arg_access_qual !4 !kernel_arg_type !5 !kernel_arg_base_type !5 !kernel_arg_type_qual !6 {
+entry:
+  %a.addr = alloca float, align 4
+  %b.addr = alloca float, align 4
+  store float %a, float* %a.addr, align 4
+  store float %b, float* %b.addr, align 4
+  %0 = load float, float* %a.addr, align 4
+  %1 = load float, float* %a.addr, align 4
+  %mul = fmul contract float %0, %1
+  store float %mul, float* %b.addr, align 4
+  %2 = load float, float* %b.addr, align 4
+  %3 = load float, float* %b.addr, align 4
+  %sub = fsub reassoc float %2, %3
+  store float %sub, float* %b.addr, align 4
+  ret void
+}
+
+attributes #0 = { convergent noinline norecurse nounwind optnone "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "uniform-work-group-size"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.module.flags = !{!0}
+!opencl.ocl.version = !{!1}
+!opencl.spir.version = !{!1}
+!llvm.ident = !{!2}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 2, i32 0}
+!2 = !{!"clang version 12.0.0 (https://github.com/intel/llvm.git 5cf8088c994778561c8584d5433d7d32618725b2)"}
+!3 = !{i32 0, i32 0}
+!4 = !{!"none", !"none"}
+!5 = !{!"float", !"float"}
+!6 = !{!"", !""}