Changed the encoding of X86 floating point stack operations where both operands

are st(0).  These can be encoded using an opcode for storing in st(0) or using
an opcode for storing in st(i), where i can also be 0.  To allow testing with
the darwin assembler and get a matching binary the opcode for storing in st(0)
is now used.  To do this the same logical trick is use from the darwin assembler
in converting things like this:

fmul %st(0), %st

into this:

fmul %st(0)

by looking for the second operand being X86::ST0 for specific floating point
mnemonics then removing the second X86::ST0 operand.  This also has the add
benefit to allow things like:

fmul %st(1), %st

that llvm-mc did not assemble.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104634 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/AsmParser/X86AsmParser.cpp b/lib/Target/X86/AsmParser/X86AsmParser.cpp
index f1e8958f503eeccc50a8f90d9ad0eb5899a51d36..40a6a7b561696b92894451c9ff7773b6d67abbad 100644 (file)
--- a/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -706,6 +706,17 @@ ParseInstruction(const StringRef &Name, SMLoc NameLoc,
     Operands.erase(Operands.begin() + 1);
   }
 
+  // FIXME: Hack to handle "f{mul*,add*,sub*,div*} $op, st(0)" the same as
+  // "f{mul*,add*,sub*,div*} $op"
+  if ((Name.startswith("fmul") || Name.startswith("fadd") ||
+       Name.startswith("fsub") || Name.startswith("fdiv")) &&
+      Operands.size() == 3 &&
+      static_cast<X86Operand*>(Operands[2])->isReg() &&
+      static_cast<X86Operand*>(Operands[2])->getReg() == X86::ST0) {
+    delete Operands[2];
+    Operands.erase(Operands.begin() + 2);
+  }
+
   return false;
 }
 

diff --git a/test/MC/AsmParser/X86/x86_32-new-encoder.s b/test/MC/AsmParser/X86/x86_32-new-encoder.s
index 19af126027ee546bc91b4db2e4b987dd78b7d678..82df362cb82f88663bf3a9de6ce5a65ffd349bce 100644 (file)
--- a/test/MC/AsmParser/X86/x86_32-new-encoder.s
+++ b/test/MC/AsmParser/X86/x86_32-new-encoder.s
@@ -277,3 +277,28 @@ retl
 // CHECK: cmpsd $7, %xmm0, %xmm1
 // CHECK: encoding: [0xf2,0x0f,0xc2,0xc8,0x07]
         cmpordsd %xmm0, %xmm1
+
+// rdar://7995856
+// CHECK: fmul %st(0)
+// CHECK:  encoding: [0xd8,0xc8]
+        fmul %st(0), %st
+
+// CHECK: fadd %st(0)
+// CHECK:  encoding: [0xd8,0xc0]
+        fadd %st(0), %st
+
+// CHECK: fsub %st(0)
+// CHECK:  encoding: [0xd8,0xe0]
+        fsub %st(0), %st
+
+// CHECK: fsubr        %st(0)
+// CHECK:  encoding: [0xd8,0xe8]
+        fsubr %st(0), %st
+
+// CHECK: fdivr        %st(0)
+// CHECK:  encoding: [0xd8,0xf8]
+        fdivr %st(0), %st
+
+// CHECK: fdiv %st(0)
+// CHECK:  encoding: [0xd8,0xf0]
+        fdiv %st(0), %st