[X86][AVX] Extend hasVEX_WPrefix bit to accept WIG value (W Ignore) +…

… update all AVX instructions with the new value.

Add WIG value to all of AVX instructions which ignore the W-bit in their encoding, instead of giving them the default value of 0.
This patch is needed for a follow up work on EVEX2VEX pass (replacing EVEX encoded instructions with their corresponding VEX version when possible).

Differential Revision: https://reviews.llvm.org/D29876

llvm-svn: 295643

llvm/lib/Target/X86/X86InstrFormats.td

@@ -199,7 +199,8 @@ class TAPS : TA { Prefix OpPrefix = PS; }
 class TAPD : TA { Prefix OpPrefix = PD; }
 class TAXD : TA { Prefix OpPrefix = XD; }
 class VEX    { Encoding OpEnc = EncVEX; }
-class VEX_W  { bit hasVEX_WPrefix = 1; }
+class VEX_W    { bits<2> VEX_WPrefix = 1; }
+class VEX_WIG  { bits<2> VEX_WPrefix = 2; }
 class VEX_4V : VEX { bit hasVEX_4V = 1; }
 class VEX_L  { bit hasVEX_L = 1; }
 class VEX_LIG { bit ignoresVEX_L = 1; }
@@ -270,7 +271,7 @@ class X86Inst<bits<8> opcod, Format f, ImmType i, dag outs, dag ins,
   bit hasREPPrefix = 0;     // Does this inst have a REP prefix?
   Encoding OpEnc = EncNormal; // Encoding used by this instruction
   bits<2> OpEncBits = OpEnc.Value;
-  bit hasVEX_WPrefix = 0;   // Does this inst set the VEX_W field?
+  bits<2> VEX_WPrefix = 0;  // Does this inst set the VEX_W field?
   bit hasVEX_4V = 0;        // Does this inst require the VEX.VVVV field?
   bit hasVEX_L = 0;         // Does this inst use large (256-bit) registers?
   bit ignoresVEX_L = 0;     // Does this instruction ignore the L-bit
@@ -317,7 +318,8 @@ class X86Inst<bits<8> opcod, Format f, ImmType i, dag outs, dag ins,
   let TSFlags{28-27} = ExeDomain.Value;
   let TSFlags{30-29} = OpEncBits;
   let TSFlags{38-31} = Opcode;
-  let TSFlags{39}    = hasVEX_WPrefix;
+  // Currently no need for second bit in TSFlags - W Ignore is equivalent to 0.
+  let TSFlags{39}    = VEX_WPrefix{0};
   let TSFlags{40}    = hasVEX_4V;
   let TSFlags{41}    = hasVEX_L;
   let TSFlags{42}    = hasEVEX_K;