[SYCL] Relax work-group metadata generation and processing in sycl-post-link (#7471)

When generating program metadata for `reqd_work_group_size` information
sycl-post-link currently expects the existence of all three dimensions
in the metadata. As a result the compile-time kernel property
`work_group_size` needs to pad itself to adhere to this requirement.
This commit relaxes the requirement by instead allowing fewer than three
metadata operands in both `reqd_work_group_size` and
`work_group_size_hint` when generating the program metadata.
Additionally, padding will no longer be added when converting
"sycl-work-group-size" and "sycl-work-group-size-hint" into the
corresponding metadata.

Signed-off-by: Larsen, Steffen <steffen.larsen@intel.com>

Author: steffenlarsen

llvm/test/tools/sycl-post-link/emit_program_metadata.ll

@@ -7,8 +7,12 @@
 target triple = "spir64-unknown-unknown"
 
 attributes #0 = { "sycl-work-group-size"="4,2,1" }
+attributes #1 = { "sycl-work-group-size"="4,2" }
+attributes #2 = { "sycl-work-group-size"="4" }
 
 !0 = !{i32 1, i32 2, i32 4}
+!1 = !{i32 2, i32 4}
+!2 = !{i32 4}
 
 define weak_odr spir_kernel void @SpirKernel1(float %arg1) !reqd_work_group_size !0 {
   call void @foo(float %arg1)
@@ -20,12 +24,36 @@ define weak_odr spir_kernel void @SpirKernel2(float %arg1) #0 {
   ret void
 }
 
+define weak_odr spir_kernel void @SpirKernel3(float %arg1) !reqd_work_group_size !1 {
+  call void @foo(float %arg1)
+  ret void
+}
+
+define weak_odr spir_kernel void @SpirKernel4(float %arg1) #1 {
+  call void @foo(float %arg1)
+  ret void
+}
+
+define weak_odr spir_kernel void @SpirKernel5(float %arg1) !reqd_work_group_size !2 {
+  call void @foo(float %arg1)
+  ret void
+}
+
+define weak_odr spir_kernel void @SpirKernel6(float %arg1) #2 {
+  call void @foo(float %arg1)
+  ret void
+}
+
 declare void @foo(float)
 
 ; CHECK-PROP: [SYCL/program metadata]
 ; // Base64 encoding in the prop file (including 8 bytes length):
 ; CHECK-PROP-NEXT: SpirKernel1@reqd_work_group_size=2|gBAAAAAAAAQAAAAACAAAAQAAAAA
 ; CHECK-PROP-NEXT: SpirKernel2@reqd_work_group_size=2|gBAAAAAAAAQAAAAACAAAAQAAAAA
+; CHECK-PROP-NEXT: SpirKernel3@reqd_work_group_size=2|ABAAAAAAAAgAAAAAEAAAAA
+; CHECK-PROP-NEXT: SpirKernel4@reqd_work_group_size=2|ABAAAAAAAAgAAAAAEAAAAA
+; CHECK-PROP-NEXT: SpirKernel5@reqd_work_group_size=2|gAAAAAAAAAABAAAA
+; CHECK-PROP-NEXT: SpirKernel6@reqd_work_group_size=2|gAAAAAAAAAABAAAA
 
 ; CHECK-TABLE: [Code|Properties]
 ; CHECK-TABLE-NEXT: {{.*}}files_0.prop

llvm/test/tools/sycl-post-link/kernel-properties.ll

@@ -36,11 +36,10 @@ attributes #2 = { convergent norecurse "frame-pointer"="all" "min-legal-vector-w
 !3 = !{i32 1, !"wchar_size", i32 4}
 !4 = !{i32 7, !"frame-pointer", i32 2}
 
-; Note that work-group sizes are padded with 1's after being reversed.
 ; CHECK-IR-DAG: ![[SGSizeMD0]] = !{i32 3}
-; CHECK-IR-DAG: ![[WGSizeMD0]] = !{i{{[0-9]+}} 1, i{{[0-9]+}} 1, i{{[0-9]+}} 1}
-; CHECK-IR-DAG: ![[WGSizeHintMD0]] = !{i{{[0-9]+}} 2, i{{[0-9]+}} 1, i{{[0-9]+}} 1}
-; CHECK-IR-DAG: ![[WGSizeMD1]] = !{i{{[0-9]+}} 5, i{{[0-9]+}} 4, i{{[0-9]+}} 1}
-; CHECK-IR-DAG: ![[WGSizeHintMD1]] = !{i{{[0-9]+}} 7, i{{[0-9]+}} 6, i{{[0-9]+}} 1}
+; CHECK-IR-DAG: ![[WGSizeMD0]] = !{i{{[0-9]+}} 1}
+; CHECK-IR-DAG: ![[WGSizeHintMD0]] = !{i{{[0-9]+}} 2}
+; CHECK-IR-DAG: ![[WGSizeMD1]] = !{i{{[0-9]+}} 5, i{{[0-9]+}} 4}
+; CHECK-IR-DAG: ![[WGSizeHintMD1]] = !{i{{[0-9]+}} 7, i{{[0-9]+}} 6}
 ; CHECK-IR-DAG: ![[WGSizeMD2]] = !{i{{[0-9]+}} 10, i{{[0-9]+}} 9, i{{[0-9]+}} 8}
 ; CHECK-IR-DAG: ![[WGSizeHintMD2]] = !{i{{[0-9]+}} 13, i{{[0-9]+}} 12, i{{[0-9]+}} 11}

llvm/tools/sycl-post-link/CompileTimePropertiesPass.cpp

@@ -186,12 +186,6 @@ attributeToExecModeMetadata(Module &M, const Attribute &Attr) {
       MDVals.push_back(ConstantAsMetadata::get(Constant::getIntegerValue(
           SizeTTy, APInt(SizeTBitSize, ValStr, 10))));
 
-    // The SPIR-V translator expects 3 values, so we pad the remaining
-    // dimensions with 1.
-    for (size_t I = MDVals.size(); I < 3; ++I)
-      MDVals.push_back(ConstantAsMetadata::get(
-          Constant::getIntegerValue(SizeTTy, APInt(SizeTBitSize, 1))));
-
     const char *MDName = (AttrKindStr == "sycl-work-group-size")
                              ? "reqd_work_group_size"
                              : "work_group_size_hint";

llvm/tools/sycl-post-link/sycl-post-link.cpp

@@ -302,18 +302,17 @@ std::vector<StringRef> getKernelNamesUsingAssert(const Module &M) {
 
 // Gets reqd_work_group_size information for function Func.
 std::vector<uint32_t> getKernelReqdWorkGroupSizeMetadata(const Function &Func) {
-  auto *ReqdWorkGroupSizeMD = Func.getMetadata("reqd_work_group_size");
+  MDNode *ReqdWorkGroupSizeMD = Func.getMetadata("reqd_work_group_size");
   if (!ReqdWorkGroupSizeMD)
     return {};
-  // TODO: Remove 3-operand assumption when it is relaxed.
-  assert(ReqdWorkGroupSizeMD->getNumOperands() == 3);
-  uint32_t X = mdconst::extract<ConstantInt>(ReqdWorkGroupSizeMD->getOperand(0))
-                   ->getZExtValue();
-  uint32_t Y = mdconst::extract<ConstantInt>(ReqdWorkGroupSizeMD->getOperand(1))
-                   ->getZExtValue();
-  uint32_t Z = mdconst::extract<ConstantInt>(ReqdWorkGroupSizeMD->getOperand(2))
-                   ->getZExtValue();
-  return {X, Y, Z};
+  size_t NumOperands = ReqdWorkGroupSizeMD->getNumOperands();
+  assert(NumOperands >= 1 && NumOperands <= 3 &&
+         "reqd_work_group_size does not have between 1 and 3 operands.");
+  std::vector<uint32_t> OutVals;
+  OutVals.reserve(NumOperands);
+  for (const MDOperand &MDOp : ReqdWorkGroupSizeMD->operands())
+    OutVals.push_back(mdconst::extract<ConstantInt>(MDOp)->getZExtValue());
+  return OutVals;
 }
 
 // Creates a filename based on current output filename, given extension,