[PATCH] D89021: BPF: fix incorrect DAG2DAG load optimization

[Yonghong Song via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG316117216867: BPF: fix incorrect DAG2DAG load optimization (authored by yonghong-song).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D89021/new/

https://reviews.llvm.org/D89021

Files:
  llvm/lib/Target/BPF/BPFISelDAGToDAG.cpp
  llvm/test/CodeGen/BPF/rodata_6.ll
  llvm/test/CodeGen/BPF/rodata_7.ll


Index: llvm/test/CodeGen/BPF/rodata_7.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/BPF/rodata_7.ll
@@ -0,0 +1,25 @@
+; RUN: llc -march=bpf < %s | FileCheck %s
+;
+; Source code:
+;   struct t1 { int a; };
+;   volatile const struct t1 data = { .a = 3 };
+;   int foo(void) {
+;     return data.a + 20;
+;   }
+; Compilation flag:
+;   clang -target bpf -O2 -S -emit-llvm test.c
+
+%struct.t1 = type { i32 }
+
+ at data = dso_local constant %struct.t1 { i32 3 }, align 4
+
+; Function Attrs: nofree norecurse nounwind
+define dso_local i32 @foo() local_unnamed_addr {
+entry:
+  %0 = load volatile i32, i32* getelementptr inbounds (%struct.t1, %struct.t1* @data, i64 0, i32 0), align 4
+  %add = add nsw i32 %0, 20
+; CHECK:   [[REG1:r[0-9]+]] = data ll
+; CHECK:   r0 = *(u32 *)([[REG1]] + 0)
+; CHECK:   r0 += 20
+  ret i32 %add
+}
Index: llvm/test/CodeGen/BPF/rodata_6.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/BPF/rodata_6.ll
@@ -0,0 +1,25 @@
+; RUN: llc -march=bpf < %s | FileCheck %s
+;
+; Source code:
+;   struct t1 { int a; };
+;   struct t1 data = { .a = 3 };
+;   int foo(void) {
+;     return data.a + 20;
+;   }
+; Compilation flag:
+;   clang -target bpf -O2 -S -emit-llvm test.c
+
+%struct.t1 = type { i32 }
+
+ at data = dso_local local_unnamed_addr global %struct.t1 { i32 3 }, align 4
+
+; Function Attrs: norecurse nounwind readonly
+define dso_local i32 @foo() local_unnamed_addr {
+entry:
+  %0 = load i32, i32* getelementptr inbounds (%struct.t1, %struct.t1* @data, i64 0, i32 0), align 4
+  %add = add nsw i32 %0, 20
+; CHECK:   [[REG1:r[0-9]+]] = data ll
+; CHECK:   r0 = *(u32 *)([[REG1]] + 0)
+; CHECK:   r0 += 20
+  ret i32 %add
+}
Index: llvm/lib/Target/BPF/BPFISelDAGToDAG.cpp
===================================================================
--- llvm/lib/Target/BPF/BPFISelDAGToDAG.cpp
+++ llvm/lib/Target/BPF/BPFISelDAGToDAG.cpp
@@ -254,7 +254,7 @@
   const LoadSDNode *LD = cast<LoadSDNode>(Node);
   uint64_t size = LD->getMemOperand()->getSize();
 
-  if (!size || size > 8 || (size & (size - 1)))
+  if (!size || size > 8 || (size & (size - 1)) || !LD->isSimple())
     return;
 
   SDNode *LDAddrNode = LD->getOperand(1).getNode();
@@ -342,7 +342,7 @@
                                             unsigned char *ByteSeq) {
   const GlobalVariable *V = dyn_cast<GlobalVariable>(Node->getGlobal());
 
-  if (!V || !V->hasInitializer())
+  if (!V || !V->hasInitializer() || !V->isConstant())
     return false;
 
   const Constant *Init = V->getInitializer();


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