Consistently use MemoryLocation::UnknownSize to indicate unknown access size

1. Change the software pipeliner to use unknown size instead of dropping
   memory operands. It used to do it before, but MachineInstr::mayAlias
   did not handle it correctly.
2. Recognize UnknownSize in MachineInstr::mayAlias.
3. Print and parse UnknownSize in MIR.

Differential Revision: https://reviews.llvm.org/D50339

llvm-svn: 340208

3 files changed, 15 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/MIRParser/MILexer.cpp b/llvm/lib/CodeGen/MIRParser/MILexer.cpp
index 400e0981a16..e3f19f011ce 100644
--- a/llvm/lib/CodeGen/MIRParser/MILexer.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MILexer.cpp
@@ -247,6 +247,7 @@ static MIToken::TokenKind getIdentifierKind(StringRef Identifier) {
       .Case("intpred", MIToken::kw_intpred)
       .Case("pre-instr-symbol", MIToken::kw_pre_instr_symbol)
       .Case("post-instr-symbol", MIToken::kw_post_instr_symbol)
+      .Case("unknown-size", MIToken::kw_unknown_size)
       .Default(MIToken::Identifier);
 }
 
diff --git a/llvm/lib/CodeGen/MIRParser/MILexer.h b/llvm/lib/CodeGen/MIRParser/MILexer.h
index 94b460e9ac2..d2dc5511b25 100644
--- a/llvm/lib/CodeGen/MIRParser/MILexer.h
+++ b/llvm/lib/CodeGen/MIRParser/MILexer.h
@@ -115,6 +115,7 @@ struct MIToken {
     kw_intpred,
     kw_pre_instr_symbol,
     kw_post_instr_symbol,
+    kw_unknown_size,
 
     // Named metadata keywords
     md_tbaa,
diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index 956f6eceb82..7ba75c13084 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -24,6 +24,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/Analysis/MemoryLocation.h"
 #include "llvm/AsmParser/Parser.h"
 #include "llvm/AsmParser/SlotMapping.h"
 #include "llvm/CodeGen/MIRPrinter.h"
@@ -2452,7 +2453,7 @@ bool MIParser::parseOptionalAtomicOrdering(AtomicOrdering &Order) {
     return false;
   }
 
-  return error("expected an atomic scope, ordering or a size integer literal");
+  return error("expected an atomic scope, ordering or a size specification");
 }
 
 bool MIParser::parseMachineMemoryOperand(MachineMemOperand *&Dest) {
@@ -2491,11 +2492,17 @@ bool MIParser::parseMachineMemoryOperand(MachineMemOperand *&Dest) {
   if (parseOptionalAtomicOrdering(FailureOrder))
     return true;
 
-  if (Token.isNot(MIToken::IntegerLiteral))
-    return error("expected the size integer literal after memory operation");
+  if (Token.isNot(MIToken::IntegerLiteral) &&
+      Token.isNot(MIToken::kw_unknown_size))
+    return error("expected the size integer literal or 'unknown-size' after "
+                 "memory operation");
   uint64_t Size;
-  if (getUint64(Size))
-    return true;
+  if (Token.is(MIToken::IntegerLiteral)) {
+    if (getUint64(Size))
+      return true;
+  } else if (Token.is(MIToken::kw_unknown_size)) {
+    Size = MemoryLocation::UnknownSize;
+  }
   lex();
 
   MachinePointerInfo Ptr = MachinePointerInfo();
@@ -2512,7 +2519,7 @@ bool MIParser::parseMachineMemoryOperand(MachineMemOperand *&Dest) {
     if (parseMachinePointerInfo(Ptr))
       return true;
   }
-  unsigned BaseAlignment = Size;
+  unsigned BaseAlignment = (Size != MemoryLocation::UnknownSize ? Size : 1);
   AAMDNodes AAInfo;
   MDNode *Range = nullptr;
   while (consumeIfPresent(MIToken::comma)) {