[SPIR-V] Fix legalize info for G_BITREVERSE (#93699)

This PR fixes legalize info for G_BITREVERSE.

Author: VyacheslavLevytskyy

llvm/lib/Target/SPIRV/SPIRVLegalizerInfo.cpp

@@ -182,7 +182,7 @@ SPIRVLegalizerInfo::SPIRVLegalizerInfo(const SPIRVSubtarget &ST) {
 
   getActionDefinitionsBuilder({G_LOAD, G_STORE}).legalIf(typeInSet(1, allPtrs));
 
-  getActionDefinitionsBuilder(G_BITREVERSE).legalFor(allFloatScalarsAndVectors);
+  getActionDefinitionsBuilder(G_BITREVERSE).legalFor(allIntScalarsAndVectors);
 
   getActionDefinitionsBuilder(G_FMA).legalFor(allFloatScalarsAndVectors);
 

llvm/lib/Target/SPIRV/SPIRVPreLegalizer.cpp

@@ -472,6 +472,11 @@ generateAssignInstrs(MachineFunction &MF, SPIRVGlobalRegistry *GR,
         insertAssignInstr(Reg, Ty, nullptr, GR, MIB, MRI);
       } else if (MIOp == TargetOpcode::G_GLOBAL_VALUE) {
         propagateSPIRVType(&MI, GR, MRI, MIB);
+      } else if (MIOp == TargetOpcode::G_BITREVERSE) {
+        Register Reg = MI.getOperand(0).getReg();
+        LLT RegType = MRI.getType(Reg);
+        if (RegType.getSizeInBits() < 32)
+          MRI.setType(Reg, LLT::scalar(32));
       }
 
       if (MII == Begin)

llvm/test/CodeGen/SPIRV/transcoding/OpBitReverse_i2.ll

@@ -0,0 +1,21 @@
+; The goal of the test case is to ensure that there's no crash
+; on translation of integers with bit width less than 8.
+
+; RUN: llc -O0 -mtriple=spirv64-unknown-unknown %s --spirv-ext=+SPV_KHR_bit_instructions -o - | FileCheck %s --check-prefix=CHECK-SPIRV
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown %s --spirv-ext=+SPV_KHR_bit_instructions -o - -filetype=obj | spirv-val %}
+
+; RUN: llc -O0 -mtriple=spirv32-unknown-unknown %s --spirv-ext=+SPV_KHR_bit_instructions -o - | FileCheck %s --check-prefix=CHECK-SPIRV
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv32-unknown-unknown %s --spirv-ext=+SPV_KHR_bit_instructions -o - -filetype=obj | spirv-val %}
+
+; CHECK-SPIRV: OpCapability BitInstructions
+; CHECK-SPIRV: OpExtension "SPV_KHR_bit_instructions"
+; CHECK-SPIRV: %[[#CharTy:]] = OpTypeInt 8 0
+; CHECK-SPIRV: %[[#]] = OpBitReverse %[[#CharTy]] %[[#]]
+
+define spir_func signext i2 @foo(i2 noundef signext %a) {
+entry:
+  %b = tail call i2 @llvm.bitreverse.i2(i2 %a)
+  ret i2 %b
+}
+
+declare i2 @llvm.bitreverse.i2(i2)