[AVX512][inline-asm] Fix AVX512 inline assembly instruction resolution when the size...

This commit handles cases where the size qualifier of an indirect memory reference operand in Intel syntax is missing (e.g. "vaddps xmm1, xmm2, [a]").

GCC will deduce the size qualifier for AVX512 vector and broadcast memory operands based on the possible matches:
"vaddps xmm1, xmm2, [a]" matches only “XMMWORD PTR” qualifier.
"vaddps xmm1, xmm2, [a]{1to4}" matches only “DWORD PTR” qualifier.

This is different from the current behavior of LLVM, which deduces the size qualifier based on the size of the memory operand.
For "vaddps xmm1, xmm2, [a]"
"char a;" will imply "BYTE PTR" qualifier
"short a;" will imply "WORD PTR" qualifier.

This commit aligns LLVM to GCC’s behavior.

This is the LLVM part of the review.
The Clang part of the review: https://reviews.llvm.org/D26587

Differential Revision: https://reviews.llvm.org/D26586

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287630 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/AsmParser/X86AsmParser.cpp b/lib/Target/X86/AsmParser/X86AsmParser.cpp
index d01e33f3f765885650ce34e047042adedb6952d9..6e3948eedf345ffad17f584f7ba28be21119c016 100644 (file)
--- a/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -722,7 +722,8 @@ private:
   CreateMemForInlineAsm(unsigned SegReg, const MCExpr *Disp, unsigned BaseReg,
                         unsigned IndexReg, unsigned Scale, SMLoc Start,
                         SMLoc End, unsigned Size, StringRef Identifier,
-                        InlineAsmIdentifierInfo &Info);
+                        InlineAsmIdentifierInfo &Info,
+                        bool AllowBetterSizeMatch = false);
 
   bool parseDirectiveEven(SMLoc L);
   bool ParseDirectiveWord(unsigned Size, SMLoc L);
@@ -765,6 +766,11 @@ private:
 
   bool ParseZ(std::unique_ptr<X86Operand> &Z, const SMLoc &StartLoc);
 
+  /// MS-compatibility:
+  /// Obtain an appropriate size qualifier, when facing its absence,
+  /// upon AVX512 vector/broadcast memory operand
+  unsigned AdjustAVX512Mem(unsigned Size, X86Operand* UnsizedMemOpNext);
+
   bool is64BitMode() const {
     // FIXME: Can tablegen auto-generate this?
     return getSTI().getFeatureBits()[X86::Mode64Bit];
@@ -1172,7 +1178,7 @@ static unsigned getIntelMemOperandSize(StringRef OpStr) {
 std::unique_ptr<X86Operand> X86AsmParser::CreateMemForInlineAsm(
     unsigned SegReg, const MCExpr *Disp, unsigned BaseReg, unsigned IndexReg,
     unsigned Scale, SMLoc Start, SMLoc End, unsigned Size, StringRef Identifier,
-    InlineAsmIdentifierInfo &Info) {
+    InlineAsmIdentifierInfo &Info, bool AllowBetterSizeMatch) {
   // If we found a decl other than a VarDecl, then assume it is a FuncDecl or
   // some other label reference.
   if (isa<MCSymbolRefExpr>(Disp) && Info.OpDecl && !Info.IsVarDecl) {
@@ -1201,6 +1207,13 @@ std::unique_ptr<X86Operand> X86AsmParser::CreateMemForInlineAsm(
       if (Size)
         InstInfo->AsmRewrites->emplace_back(AOK_SizeDirective, Start,
                                             /*Len=*/0, Size);
+    if (AllowBetterSizeMatch)
+      // Handle cases where size qualifier is absent, upon an indirect symbol
+      // reference - e.g. "vaddps zmm1, zmm2, [var]"
+      // set Size to zero to allow matching mechansim to try and find a better
+      // size qualifier than our initial guess, based on available variants of
+      // the given instruction
+      Size = 0;
     }
   }
 
@@ -1487,7 +1500,8 @@ X86AsmParser::ParseIntelBracExpression(unsigned SegReg, SMLoc Start,
 
   InlineAsmIdentifierInfo &Info = SM.getIdentifierInfo();
   return CreateMemForInlineAsm(SegReg, Disp, BaseReg, IndexReg, Scale, Start,
-                               End, Size, SM.getSymName(), Info);
+                               End, Size, SM.getSymName(), Info,
+                               isParsingInlineAsm());
 }
 
 // Inline assembly may use variable names with namespace alias qualifiers.
@@ -2828,6 +2842,23 @@ bool X86AsmParser::MatchAndEmitATTInstruction(SMLoc IDLoc, unsigned &Opcode,
   return true;
 }
 
+unsigned X86AsmParser::AdjustAVX512Mem(unsigned Size,
+    X86Operand* UnsizedMemOpNext) {
+  // Check for the existence of an AVX512 platform
+  if (!getSTI().getFeatureBits()[X86::FeatureAVX512])
+    return 0;
+  // Allow adjusting upon a (x|y|z)mm
+  if (Size == 512 || Size == 256 || Size == 128)
+    return Size;
+  // This is an allegadly broadcasting mem op adjustment,
+  // allow some more inquiring to validate it
+  if (Size == 64 || Size == 32)
+    return UnsizedMemOpNext && UnsizedMemOpNext->isToken() &&
+      UnsizedMemOpNext->getToken().substr(0, 4).equals("{1to") ? Size : 0;
+  // Do not allow any other type of adjustments
+  return 0;
+}
+
 bool X86AsmParser::MatchAndEmitIntelInstruction(SMLoc IDLoc, unsigned &Opcode,
                                                 OperandVector &Operands,
                                                 MCStreamer &Out,
@@ -2847,8 +2878,17 @@ bool X86AsmParser::MatchAndEmitIntelInstruction(SMLoc IDLoc, unsigned &Opcode,
 
   // Find one unsized memory operand, if present.
   X86Operand *UnsizedMemOp = nullptr;
+  // If unsized memory operand was found - obtain following operand.
+  // For use in AdjustAVX512Mem
+  X86Operand *UnsizedMemOpNext = nullptr;
   for (const auto &Op : Operands) {
     X86Operand *X86Op = static_cast<X86Operand *>(Op.get());
+    if (UnsizedMemOp) {
+      UnsizedMemOpNext = X86Op;
+      // Have we found an unqualified memory operand,
+      // break. IA allows only one memory operand.
+      break;
+    }
     if (X86Op->isMemUnsized())
       UnsizedMemOp = X86Op;
   }
@@ -2896,6 +2936,7 @@ bool X86AsmParser::MatchAndEmitIntelInstruction(SMLoc IDLoc, unsigned &Opcode,
   // If an unsized memory operand is present, try to match with each memory
   // operand size.  In Intel assembly, the size is not part of the instruction
   // mnemonic.
+  unsigned MatchedSize = 0;
   if (UnsizedMemOp && UnsizedMemOp->isMemUnsized()) {
     static const unsigned MopSizes[] = {8, 16, 32, 64, 80, 128, 256, 512};
     for (unsigned Size : MopSizes) {
@@ -2910,6 +2951,12 @@ bool X86AsmParser::MatchAndEmitIntelInstruction(SMLoc IDLoc, unsigned &Opcode,
       // If this returned as a missing feature failure, remember that.
       if (Match.back() == Match_MissingFeature)
         ErrorInfoMissingFeature = ErrorInfoIgnore;
+      if (M == Match_Success)
+        // MS-compatability:
+        // Adjust AVX512 vector/broadcast memory operand,
+        // when facing the absence of a size qualifier.
+        // Match GCC behavior on respective cases.
+        MatchedSize = AdjustAVX512Mem(Size, UnsizedMemOpNext);
     }
 
     // Restore the size of the unsized memory operand if we modified it.
@@ -2944,6 +2991,14 @@ bool X86AsmParser::MatchAndEmitIntelInstruction(SMLoc IDLoc, unsigned &Opcode,
   unsigned NumSuccessfulMatches =
       std::count(std::begin(Match), std::end(Match), Match_Success);
   if (NumSuccessfulMatches == 1) {
+    if (MatchedSize && isParsingInlineAsm() && isParsingIntelSyntax())
+      // MS compatibility -
+      // Fix the rewrite according to the matched memory size
+      // MS inline assembly only
+      for (AsmRewrite &AR : *InstInfo->AsmRewrites)
+        if ((AR.Loc.getPointer() == UnsizedMemOp->StartLoc.getPointer()) &&
+            (AR.Kind == AOK_SizeDirective))
+          AR.Val = MatchedSize;
     // Some instructions need post-processing to, for example, tweak which
     // encoding is selected. Loop on it while changes happen so the individual
     // transformations can chain off each other.