Support lowering of constant expression vectors inside metadata (#1175)

Author: Fznamznon

lib/SPIRV/SPIRVLowerConstExpr.cpp

@@ -167,22 +167,23 @@ void SPIRVLowerConstExprBase::visit(Module *M) {
       };
 
       WorkList.pop_front();
-      for (unsigned OI = 0, OE = II->getNumOperands(); OI != OE; ++OI) {
-        auto Op = II->getOperand(OI);
-        auto *Vec = dyn_cast<ConstantVector>(Op);
-        if (Vec && std::all_of(Vec->op_begin(), Vec->op_end(), [](Value *V) {
+      auto LowerConstantVec = [&II, &LowerOp, &WorkList,
+                               &M](ConstantVector *Vec,
+                                   unsigned NumOfOp) -> Value * {
+        if (std::all_of(Vec->op_begin(), Vec->op_end(), [](Value *V) {
               return isa<ConstantExpr>(V) || isa<Function>(V);
             })) {
-          // Expand a vector of constexprs and construct it back with series of
-          // insertelement instructions
+          // Expand a vector of constexprs and construct it back with
+          // series of insertelement instructions
           std::list<Value *> OpList;
           std::transform(Vec->op_begin(), Vec->op_end(),
                          std::back_inserter(OpList),
                          [LowerOp](Value *V) { return LowerOp(V); });
           Value *Repl = nullptr;
           unsigned Idx = 0;
           auto *PhiII = dyn_cast<PHINode>(II);
-          auto *InsPoint = PhiII ? &PhiII->getIncomingBlock(OI)->back() : II;
+          auto *InsPoint =
+              PhiII ? &PhiII->getIncomingBlock(NumOfOp)->back() : II;
           std::list<Instruction *> ReplList;
           for (auto V : OpList) {
             if (auto *Inst = dyn_cast<Instruction>(V))
@@ -192,20 +193,34 @@ void SPIRVLowerConstExprBase::visit(Module *M) {
                 ConstantInt::get(Type::getInt32Ty(M->getContext()), Idx++), "",
                 InsPoint);
           }
-          II->replaceUsesOfWith(Op, Repl);
           WorkList.splice(WorkList.begin(), ReplList);
+          return Repl;
+        }
+        return nullptr;
+      };
+
+      for (unsigned OI = 0, OE = II->getNumOperands(); OI != OE; ++OI) {
+        auto *Op = II->getOperand(OI);
+        if (auto *Vec = dyn_cast<ConstantVector>(Op)) {
+          Value *ReplInst = LowerConstantVec(Vec, OI);
+          if (ReplInst)
+            II->replaceUsesOfWith(Op, ReplInst);
         } else if (auto CE = dyn_cast<ConstantExpr>(Op)) {
           WorkList.push_front(cast<Instruction>(LowerOp(CE)));
         } else if (auto MDAsVal = dyn_cast<MetadataAsValue>(Op)) {
           Metadata *MD = MDAsVal->getMetadata();
           if (auto ConstMD = dyn_cast<ConstantAsMetadata>(MD)) {
             Constant *C = ConstMD->getValue();
-            if (auto CE = dyn_cast<ConstantExpr>(C)) {
-              Value *RepInst = LowerOp(CE);
-              Metadata *RepMD = ValueAsMetadata::get(RepInst);
+            Value *ReplInst = nullptr;
+            if (auto *Vec = dyn_cast<ConstantVector>(C))
+              ReplInst = LowerConstantVec(Vec, OI);
+            if (auto *CE = dyn_cast<ConstantExpr>(C))
+              ReplInst = LowerOp(CE);
+            if (ReplInst) {
+              Metadata *RepMD = ValueAsMetadata::get(ReplInst);
               Value *RepMDVal = MetadataAsValue::get(M->getContext(), RepMD);
               II->setOperand(OI, RepMDVal);
-              WorkList.push_front(cast<Instruction>(RepInst));
+              WorkList.push_front(cast<Instruction>(ReplInst));
             }
           }
         }

test/vector-metadata-constexpr.ll

@@ -0,0 +1,64 @@
+; RUN: llvm-as %s -o %t.bc
+; RUN: llvm-spirv -s %t.bc -o - | llvm-dis -o - | FileCheck %s
+; RUN: llvm-spirv %t.bc
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "spir64-unknown-unknown"
+
+; Function Attrs: nounwind ssp uwtable
+define void @foo() #0 !dbg !4 {
+entry:
+  call void @llvm.dbg.value(metadata <3 x i8> <i8 add (i8 extractelement (<8 x i8> bitcast (<2 x i32> <i32 65793, i32 65793> to <8 x i8>), i32 0), i8 extractelement (<8 x i8> bitcast (<2 x i32> <i32 131586, i32 131586> to <8 x i8>), i32 0)), i8 add (i8 extractelement (<8 x i8> bitcast (<2 x i32> <i32 65793, i32 65793> to <8 x i8>), i32 1), i8 extractelement (<8 x i8> bitcast (<2 x i32> <i32 131586, i32 131586> to <8 x i8>), i32 1)), i8 add (i8 extractelement (<8 x i8> bitcast (<2 x i32> <i32 65793, i32 65793> to <8 x i8>), i32 2), i8 extractelement (<8 x i8> bitcast (<2 x i32> <i32 131586, i32 131586> to <8 x i8>), i32 2))>, metadata !12, metadata !DIExpression()), !dbg !18
+  ret void, !dbg !20
+; CHECK: %0 = bitcast <2 x i32> <i32 65793, i32 65793> to <8 x i8>
+; CHECK: %1 = extractelement <8 x i8> %0, i32 0
+; CHECK: %2 = bitcast <2 x i32> <i32 131586, i32 131586> to <8 x i8>
+; CHECK: %3 = extractelement <8 x i8> %2, i32 0
+; CHECK: %4 = add i8 %1, %3
+; CHECK: %5 = bitcast <2 x i32> <i32 65793, i32 65793> to <8 x i8>
+; CHECK: %6 = extractelement <8 x i8> %5, i32 1
+; CHECK: %7 = bitcast <2 x i32> <i32 131586, i32 131586> to <8 x i8>
+; CHECK: %8 = extractelement <8 x i8> %7, i32 1
+; CHECK: %9 = add i8 %6, %8
+; CHECK: %10 = bitcast <2 x i32> <i32 65793, i32 65793> to <8 x i8>
+; CHECK: %11 = extractelement <8 x i8> %10, i32 2
+; CHECK: %12 = bitcast <2 x i32> <i32 131586, i32 131586> to <8 x i8>
+; CHECK: %13 = extractelement <8 x i8> %12, i32 2
+; CHECK: %14 = add i8 %11, %13
+; CHECK: %15 = insertelement <3 x i8> undef, i8 %4, i32 0
+; CHECK: %16 = insertelement <3 x i8> %15, i8 %9, i32 1
+; CHECK: %17 = insertelement <3 x i8> %16, i8 %14, i32 2
+; CHECK: call void @llvm.dbg.value(metadata <3 x i8> %17, metadata !{{[0-9]+}}, metadata !DIExpression()), !dbg !{{[0-9]+}}
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.value(metadata, metadata, metadata) #2
+
+attributes #0 = { nounwind ssp uwtable  }
+attributes #2 = { nounwind readnone }
+attributes #3 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!13, !14, !15}
+!llvm.ident = !{!16}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.7.0 (trunk 235110) (llvm/trunk 235108)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
+!1 = !DIFile(filename: "t.c", directory: "/path/to/dir")
+!2 = !{}
+!4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 3, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !2)
+!5 = !DISubroutineType(types: !6)
+!6 = !{null}
+!7 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 2, type: !8, isLocal: true, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !11)
+!8 = !DISubroutineType(types: !9)
+!9 = !{null, !10}
+!10 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!11 = !{!12}
+!12 = !DILocalVariable(name: "a", arg: 1, scope: !7, file: !1, line: 2, type: !10)
+!13 = !{i32 2, !"Dwarf Version", i32 2}
+!14 = !{i32 2, !"Debug Info Version", i32 3}
+!15 = !{i32 1, !"PIC Level", i32 2}
+!16 = !{!"clang version 3.7.0 (trunk 235110) (llvm/trunk 235108)"}
+!17 = !DIExpression()
+!18 = !DILocation(line: 2, column: 52, scope: !7, inlinedAt: !19)
+!19 = distinct !DILocation(line: 4, column: 3, scope: !4)
+!20 = !DILocation(line: 6, column: 1, scope: !4)