Implement enough of the missing instalias support to get

aliases installed and working.  They now work when the
matched pattern and the result instruction have exactly
the same operand list.

This is now enough for us to define proper aliases for
movzx and movsx, implementing rdar://8017633 and PR7459.

Note that we do not accept instructions like:
  movzx 0(%rsp), %rsi

GAS accepts this instruction, but it doesn't make any
sense because we don't know the size of the memory
operand.  It could be 8/16/32 bits.

llvm-svn: 117901

2 files changed, 33 insertions, 3 deletions

diff --git a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
index 28e30769abc..21faa962a91 100644
--- a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -620,9 +620,6 @@ X86Operand *X86ATTAsmParser::ParseMemOperand(unsigned SegReg, SMLoc MemStart) {
 bool X86ATTAsmParser::
 ParseInstruction(StringRef Name, SMLoc NameLoc,
                  SmallVectorImpl<MCParsedAsmOperand*> &Operands) {
-  // FIXME: This is not correct at all.
-  if (Name == "movzx") Name = "movzb";
-  
   StringRef PatchedName = Name;
 
   // FIXME: Hack to recognize cmp<comparison code>{ss,sd,ps,pd}.
diff --git a/llvm/lib/Target/X86/X86InstrInfo.td b/llvm/lib/Target/X86/X86InstrInfo.td
index ab9869abc5c..f5463c0d6ab 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.td
+++ b/llvm/lib/Target/X86/X86InstrInfo.td
@@ -1259,6 +1259,10 @@ include "X86InstrCompiler.td"
 //===----------------------------------------------------------------------===//
 
 // movsx aliases
+def : InstAlias<(outs GR16:$dst), (ins GR8 :$src),
+                "movsx $src, $dst",
+                (MOVSX16rr8W GR16:$dst, GR8:$src)>;
+
 def : InstAlias<(outs GR32:$dst), (ins GR8 :$src),
                 "movsx $src, $dst",
                 (MOVSX32rr8 GR32:$dst, GR8:$src)>;
@@ -1266,6 +1270,35 @@ def : InstAlias<(outs GR32:$dst), (ins GR16:$src),
                 "movsx $src, $dst",
                 (MOVSX32rr16 GR32:$dst, GR16:$src)>;
 
+def : InstAlias<(outs GR64:$dst), (ins GR8 :$src),
+                "movsx $src, $dst",
+                (MOVSX64rr8 GR64:$dst, GR8:$src)>;
+def : InstAlias<(outs GR64:$dst), (ins GR16:$src),
+                "movsx $src, $dst",
+                (MOVSX64rr16 GR64:$dst, GR16:$src)>;
+def : InstAlias<(outs GR64:$dst), (ins GR32:$src),
+                "movsx $src, $dst",
+                (MOVSX64rr32 GR64:$dst, GR32:$src)>;
+
+// movzx aliases
+def : InstAlias<(outs GR16:$dst), (ins GR8 :$src),
+                "movzx $src, $dst",
+                (MOVZX16rr8W GR16:$dst, GR8:$src)>;
+
+def : InstAlias<(outs GR32:$dst), (ins GR8 :$src),
+                "movzx $src, $dst",
+                (MOVZX32rr8 GR32:$dst, GR8:$src)>;
+def : InstAlias<(outs GR32:$dst), (ins GR16:$src),
+                "movzx $src, $dst",
+                (MOVZX32rr16 GR32:$dst, GR16:$src)>;
+
+def : InstAlias<(outs GR64:$dst), (ins GR8 :$src),
+                "movzx $src, $dst",
+                (MOVZX64rr8_Q GR64:$dst, GR8:$src)>;
+def : InstAlias<(outs GR64:$dst), (ins GR16:$src),
+                "movzx $src, $dst",
+                (MOVZX64rr16_Q GR64:$dst, GR16:$src)>;
+// Note: No GR32->GR64 movzx form.
 
 // TODO: lidtl/lidtq can be opcode aliases, perhaps others.