[SPIRV] Add support for SPV_KHR_bit_instructions (#66215)

Adds support for SPV_KHR_bit_instructions.

It is only used whenever we don't need the whole Shader capability, which is a superset of this extension.

Author: pmatos

llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp

@@ -15,6 +15,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "SPIRVModuleAnalysis.h"
+#include "MCTargetDesc/SPIRVBaseInfo.h"
+#include "MCTargetDesc/SPIRVMCTargetDesc.h"
 #include "SPIRV.h"
 #include "SPIRVSubtarget.h"
 #include "SPIRVTargetMachine.h"
@@ -504,7 +506,7 @@ void SPIRV::RequirementHandler::checkSatisfiable(
   for (auto Ext : AllExtensions) {
     if (ST.canUseExtension(Ext))
       continue;
-    LLVM_DEBUG(dbgs() << "Extension not suported: "
+    LLVM_DEBUG(dbgs() << "Extension not supported: "
                       << getSymbolicOperandMnemonic(
                              OperandCategory::ExtensionOperand, Ext)
                       << "\n");
@@ -523,6 +525,13 @@ void SPIRV::RequirementHandler::addAvailableCaps(const CapabilityList &ToAdd) {
           SPIRV::OperandCategory::CapabilityOperand, Cap));
 }
 
+void SPIRV::RequirementHandler::removeCapabilityIf(
+    const Capability::Capability ToRemove,
+    const Capability::Capability IfPresent) {
+  if (AvailableCaps.contains(IfPresent))
+    AvailableCaps.erase(ToRemove);
+}
+
 namespace llvm {
 namespace SPIRV {
 void RequirementHandler::initAvailableCapabilities(const SPIRVSubtarget &ST) {
@@ -734,6 +743,16 @@ void addInstrRequirements(const MachineInstr &MI,
     break;
   }
   case SPIRV::OpBitReverse:
+  case SPIRV::OpBitFieldInsert:
+  case SPIRV::OpBitFieldSExtract:
+  case SPIRV::OpBitFieldUExtract:
+    if (!ST.canUseExtension(SPIRV::Extension::SPV_KHR_bit_instructions)) {
+      Reqs.addCapability(SPIRV::Capability::Shader);
+      break;
+    }
+    Reqs.addExtension(SPIRV::Extension::SPV_KHR_bit_instructions);
+    Reqs.addCapability(SPIRV::Capability::BitInstructions);
+    break;
   case SPIRV::OpTypeRuntimeArray:
     Reqs.addCapability(SPIRV::Capability::Shader);
     break;
@@ -887,6 +906,12 @@ void addInstrRequirements(const MachineInstr &MI,
   default:
     break;
   }
+
+  // If we require capability Shader, then we can remove the requirement for
+  // the BitInstructions capability, since Shader is a superset capability
+  // of BitInstructions.
+  Reqs.removeCapabilityIf(SPIRV::Capability::BitInstructions,
+                          SPIRV::Capability::Shader);
 }
 
 static void collectReqs(const Module &M, SPIRV::ModuleAnalysisInfo &MAI,

llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.h

@@ -113,6 +113,10 @@ struct RequirementHandler {
   bool isCapabilityAvailable(Capability::Capability Cap) const {
     return AvailableCaps.contains(Cap);
   }
+
+  // Remove capability ToRemove, but only if IfPresent is present.
+  void removeCapabilityIf(const Capability::Capability ToRemove,
+                          const Capability::Capability IfPresent);
 };
 
 using InstrList = SmallVector<MachineInstr *>;

llvm/lib/Target/SPIRV/SPIRVSubtarget.cpp

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "SPIRVSubtarget.h"
+#include "MCTargetDesc/SPIRVBaseInfo.h"
 #include "SPIRV.h"
 #include "SPIRVGlobalRegistry.h"
 #include "SPIRVLegalizerInfo.h"
@@ -40,7 +41,11 @@ cl::list<SPIRV::Extension::Extension> Extensions(
         clEnumValN(SPIRV::Extension::SPV_KHR_no_integer_wrap_decoration,
                    "SPV_KHR_no_integer_wrap_decoration",
                    "Adds decorations to indicate that a given instruction does "
-                   "not cause integer wrapping")));
+                   "not cause integer wrapping"),
+        clEnumValN(SPIRV::Extension::SPV_KHR_bit_instructions,
+                   "SPV_KHR_bit_instructions",
+                   "This enables bit instructions to be used by SPIR-V modules "
+                   "without requiring the Shader capability")));
 
 // Compare version numbers, but allow 0 to mean unspecified.
 static bool isAtLeastVer(uint32_t Target, uint32_t VerToCompareTo) {

llvm/lib/Target/SPIRV/SPIRVSymbolicOperands.td

@@ -450,6 +450,7 @@ defm PhysicalStorageBufferAddressesEXT : CapabilityOperand<5347, 0, 0, [], [Shad
 defm CooperativeMatrixNV : CapabilityOperand<5357, 0, 0, [], [Shader]>;
 defm ArbitraryPrecisionIntegersINTEL : CapabilityOperand<5844, 0, 0, [SPV_INTEL_arbitrary_precision_integers], [Int8, Int16]>;
 defm OptNoneINTEL : CapabilityOperand<6094, 0, 0, [SPV_INTEL_optnone], []>;
+defm BitInstructions : CapabilityOperand<6025, 0, 0, [SPV_KHR_bit_instructions], []>;
 
 //===----------------------------------------------------------------------===//
 // Multiclass used to define SourceLanguage enum values and at the same time

llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bit_instructions.ll

@@ -0,0 +1,24 @@
+; RUN: llc -O0 -mtriple=spirv32-unknown-unknown %s --spirv-extensions=SPV_KHR_bit_instructions -o - | FileCheck %s --check-prefix=CHECK-EXTENSION
+; RUN: llc -O0 -mtriple=spirv32-unknown-unknown %s -o - | FileCheck %s --check-prefix=CHECK-NO-EXTENSION
+
+; CHECK-EXTENSION:      OpCapability BitInstructions
+; CHECK-EXTENSION-NEXT: OpExtension "SPV_KHR_bit_instructions"
+; CHECK-EXTENSION-NOT:  OpCabilitity Shader
+; CHECK-NO-EXTENSION:     OpCapability Shader
+; CHECK-NO-EXTENSION-NOT: OpCabilitity BitInstructions
+; CHECK-NO-EXTENSION-NOT: OpExtension "SPV_KHR_bit_instructions"
+
+
+; CHECK-EXTENSION: %[[#int:]] = OpTypeInt 32
+; CHECK-EXTENSION: OpBitReverse %[[#int]]
+; CHECK-NO-EXTENSION: %[[#int:]] = OpTypeInt 32
+; CHECK-NO-EXTENSION: OpBitReverse %[[#int]]
+
+define spir_kernel void @testBitRev(i32 %a, i32 %b, i32 %c, i32 addrspace(1)* nocapture %res) local_unnamed_addr {
+entry:
+  %call = tail call i32 @llvm.bitreverse.i32(i32 %b)
+  store i32 %call, i32 addrspace(1)* %res, align 4
+  ret void
+}
+
+declare i32 @llvm.bitreverse.i32(i32)