Break constexprs before SLM resolution

The same constexpr which uses SLM var may be located in different kernels/function groups. This leads to an issue while trying to replace uses of the SLM variable since its user(constexpr) is the same for different kernels which makes impossible to use different offsets for the same SLM var.
The solution is to get rid of constexprs since such issue is not possible with instructions.

Author: KorovinVlad

IGC/VectorCompiler/lib/GenXCodeGen/GenXSLMResolution.cpp

@@ -38,6 +38,7 @@ SPDX-License-Identifier: MIT
 #include "GenXUtil.h"
 
 #include "vc/Support/GenXDiagnostic.h"
+#include "vc/Utils/GenX/BreakConst.h"
 #include "vc/Utils/GenX/GlobalVariable.h"
 #include "vc/Utils/GenX/KernelInfo.h"
 #include "vc/Utils/General/Types.h"
@@ -123,16 +124,11 @@ static void lowerSlmInit(Instruction &I) {
 
 static bool isUserInList(const User &U,
                          const SmallPtrSetImpl<Function *> &FunctionSet) {
-  if (auto *I = dyn_cast<Instruction>(&U)) {
-    auto *F = I->getFunction();
-    return FunctionSet.count(F);
-  }
-  IGC_ASSERT_MESSAGE(isa<Constant>(&U), "unexpected SLM variable user");
-  // For constant user continue recursively traversing until instruction
-  // is met.
-  return llvm::any_of(U.users(), [&FunctionSet](const User *U) {
-    return isUserInList(*U, FunctionSet);
-  });
+  auto *UserInst = dyn_cast<Instruction>(&U);
+  if (!UserInst)
+    return false;
+  auto *F = UserInst->getFunction();
+  return FunctionSet.count(F);
 }
 
 static bool isBelongToKernel(const GlobalVariable &GV,
@@ -281,6 +277,11 @@ bool GenXSLMResolution::runOnModule(Module &M) {
   llvm::for_each(SLMInitToErase, [](Instruction *I) { I->eraseFromParent(); });
 
   auto SLMVars = collectSLMVariables(M);
+  if (!SLMVars.empty())
+    for (auto &F : M.functions())
+      Modified |=
+          vc::breakConstantExprs(&F, vc::LegalizationStage::NotLegalized);
+
   for (auto &F : M.functions())
     if (vc::isKernel(&F))
       Modified |= runForKernel(F, M, SLMVars);

IGC/VectorCompiler/test/GenXSLMResolution/cfg.ll

@@ -35,24 +35,25 @@ define internal spir_func i32 @bar(i32 addrspace(3)* %arg) #1 {
   ret i32 %arg.ld
 }
 
-; CHECK: define internal spir_func i32 @foo
-; CHECK: %bar.res = call spir_func i32 @bar(i32 addrspace(3)* getelementptr inbounds ([4 x i32], [4 x i32] addrspace(3)* inttoptr (i32 268435456 to [4 x i32] addrspace(3)*), i64 0, i64 1))
+; CHECK-LABEL: define internal spir_func i32 @foo
 define internal spir_func i32 @foo(i32 addrspace(3)* %arg) #1 {
+  ; CHECK: [[SPLIT_FOO:%[^ ]+]] = getelementptr inbounds [4 x i32], [4 x i32] addrspace(3)* inttoptr (i32 268435456 to [4 x i32] addrspace(3)*), i64 0, i64 1
+  ; CHECK: %bar.res = call spir_func i32 @bar(i32 addrspace(3)* [[SPLIT_FOO]])
   %arg.ld = load i32, i32 addrspace(3)* %arg, align 4
   %bar.res = call spir_func i32 @bar(i32 addrspace(3)* getelementptr inbounds ([4 x i32], [4 x i32] addrspace(3)* @SLM_GV, i64 0, i64 1))
   %res = add i32 %bar.res, %arg.ld
   ret i32 %res
 }
 
-; CHECK: define internal spir_func i32 @f1
-; CHECK: %gv.p3 = getelementptr inbounds [4 x i32], [4 x i32] addrspace(3)* inttoptr (i32 268435456 to [4 x i32] addrspace(3)*), i64 0, i64 2
+; CHECK-LABEL: define internal spir_func i32 @f1
 define internal spir_func i32 @f1() #1 {
+  ; CHECK: %gv.p3 = getelementptr inbounds [4 x i32], [4 x i32] addrspace(3)* inttoptr (i32 268435456 to [4 x i32] addrspace(3)*), i64 0, i64 2
   %gv.p3 = getelementptr inbounds [4 x i32], [4 x i32] addrspace(3)* @SLM_GV, i64 0, i64 2
   %foo.res = call spir_func i32 @foo(i32 addrspace(3)* %gv.p3)
   ret i32 %foo.res
 }
 
-; CHECK: define internal spir_func i32 @f2
+; CHECK-LABEL: define internal spir_func i32 @f2
 define internal spir_func i32 @f2() #1 {
   ; CHECK: %gv.p3.0 = getelementptr inbounds [4 x i32], [4 x i32] addrspace(3)* inttoptr (i32 268435456 to [4 x i32] addrspace(3)*), i64 0, i64
   %gv.p3.0 = getelementptr inbounds [4 x i32], [4 x i32] addrspace(3)* @SLM_GV, i64 0, i64 0
@@ -71,7 +72,7 @@ define internal spir_func i32 @f2() #1 {
   ret i32 %sum.res
 }
 
-; CHECK: define internal spir_func i32 @f0
+; CHECK-LABEL: define internal spir_func i32 @f0
 define internal spir_func i32 @f0(i32 addrspace(3)* %arg) #1 {
   %arg.ld = load i32, i32 addrspace(3)* %arg, align 4
 
@@ -93,25 +94,28 @@ exit:
   ret i32 %f0.res
 }
 
-; CHECK: define internal spir_func i32 @f3
-; CHECK: %bar.res = call spir_func i32 @bar(i32 addrspace(3)* getelementptr inbounds ([4 x i32], [4 x i32] addrspace(3)* inttoptr (i32 268435456 to [4 x i32] addrspace(3)*), i64 0, i64 0))
+; CHECK-LABEL: define internal spir_func i32 @f3
 define internal spir_func i32 @f3(i32 addrspace(3)* %arg) #1 {
+  ; CHECK: [[SPLIT_F3:%[^ ]+]] = getelementptr inbounds [4 x i32], [4 x i32] addrspace(3)* inttoptr (i32 64 to [4 x i32] addrspace(3)*), i64 0, i64 0
+  ; CHECK: %bar.res = call spir_func i32 @bar(i32 addrspace(3)* [[SPLIT_F3]])
   %bar.res = call spir_func i32 @bar(i32 addrspace(3)* getelementptr inbounds ([4 x i32], [4 x i32] addrspace(3)* @SLM_GV, i64 0, i64 0))
   %arg.ld = load i32, i32 addrspace(3)* %arg, align 4
   %sum = add i32 %bar.res, %arg.ld
   ret i32 %sum
 }
 
-; CHECK: define dllexport spir_kernel void @kernelA
-; CHECK: %res = call spir_func i32 @f0(i32 addrspace(3)* getelementptr inbounds ([4 x i32], [4 x i32] addrspace(3)* inttoptr (i32 268435456 to [4 x i32] addrspace(3)*), i64 0, i64 0))
+; CHECK-LABEL: define dllexport spir_kernel void @kernelA
 define dllexport spir_kernel void @kernelA() #2 {
+  ; CHECK: [[SPLIT_KA:%[^ ]+]] = getelementptr inbounds [4 x i32], [4 x i32] addrspace(3)* inttoptr (i32 268435456 to [4 x i32] addrspace(3)*), i64 0, i64 0
+  ; CHECK: %res = call spir_func i32 @f0(i32 addrspace(3)* [[SPLIT_KA]])
   %res = call spir_func i32 @f0(i32 addrspace(3)* getelementptr inbounds ([4 x i32], [4 x i32] addrspace(3)* @SLM_GV, i64 0, i64 0))
   ret void
 }
 
-; CHECK: define dllexport spir_kernel void @kernelB
-; CHECK: %res = call spir_func i32 @f3(i32 addrspace(3)* getelementptr inbounds ([4 x i32], [4 x i32] addrspace(3)* inttoptr (i32 64 to [4 x i32] addrspace(3)*), i64 0, i64 3))
+; CHECK-LABEL: define dllexport spir_kernel void @kernelB
 define dllexport spir_kernel void @kernelB() #2 {
+  ; CHECK: [[SPLIT_KB:%[^ ]+]] = getelementptr inbounds [4 x i32], [4 x i32] addrspace(3)* inttoptr (i32 64 to [4 x i32] addrspace(3)*), i64 0, i64 3
+  ; CHECK: %res = call spir_func i32 @f3(i32 addrspace(3)* [[SPLIT_KB]])
   %res = call spir_func i32 @f3(i32 addrspace(3)* getelementptr inbounds ([4 x i32], [4 x i32] addrspace(3)* @SLM_GV, i64 0, i64 3))
   ret void
 }