[ARM][Thumb2] support .w assembler qualifier for dmb/dsb/isb

[falstaff84]

Summary

Support the explicit wide assembler qualifier for the dmb/dsb/isb synchronization barrier instructions.

[ostannard]

These are just the aliases with the "option" operand omitted, we should also accept instructions like dmb.w sy.

[falstaff84]

• add .w alias for dmb/dsb/isb with argument

[ostannard]

LGTM, thanks.

llvm/lib/Target/ARM/ARMInstrThumb2.td

def : t2InstAlias<"cmn${p} $Rn, $Rm",
                   (t2CMNzrr GPRnopc:$Rn, rGPR:$Rm, pred:$p)>;
 def : t2InstAlias<"teq${p} $Rn, $Rm",
                   (t2TEQrr rGPR:$Rn, rGPR:$Rm, pred:$p)>;
 def : t2InstAlias<"tst${p} $Rn, $Rm",
                   (t2TSTrr rGPR:$Rn, rGPR:$Rm, pred:$p)>;
 
 // Memory barriers
 def : InstAlias<"dmb${p}", (t2DMB 0xf, pred:$p), 0>, Requires<[HasDB]>;
+def : InstAlias<"dmb${p}.w", (t2DMB 0xf, pred:$p), 0>, Requires<[HasDB]>;
 def : InstAlias<"dsb${p}", (t2DSB 0xf, pred:$p), 0>, Requires<[HasDB]>;
+def : InstAlias<"dsb${p}.w", (t2DSB 0xf, pred:$p), 0>, Requires<[HasDB]>;
 def : InstAlias<"isb${p}", (t2ISB 0xf, pred:$p), 0>, Requires<[HasDB]>;
+def : InstAlias<"isb${p}.w", (t2ISB 0xf, pred:$p), 0>, Requires<[HasDB]>;
 
 // Non-predicable aliases of a predicable DSB: the predicate is (14, 0) where
 // 14 = AL (always execute) and 0 = "instruction doesn't read the CPSR".
 def : InstAlias<"ssbb", (t2DSB 0x0, 14, 0), 1>, Requires<[HasDB, IsThumb2]>;
 def : InstAlias<"pssbb", (t2DSB 0x4, 14, 0), 1>, Requires<[HasDB, IsThumb2]>;
 
 // Armv8-R 'Data Full Barrier'
 def : InstAlias<"dfb${p}", (t2DSB 0xc, pred:$p), 1>, Requires<[HasDFB]>;

llvm/test/MC/ARM/basic-thumb2-instructions.s

@------------------------------------------------------------------------------
         dmb ishst
         dmb un
         dmb nsh
         dmb unst
         dmb nshst
         dmb osh
         dmb oshst
         dmb
+        dmb.w
 
 @ CHECK: dmb  sy                      @ encoding: [0xbf,0xf3,0x5f,0x8f]
 @ CHECK: dmb  st                      @ encoding: [0xbf,0xf3,0x5e,0x8f]
 @ CHECK: dmb  #0xd                    @ encoding: [0xbf,0xf3,0x5d,0x8f]
 @ CHECK: dmb  #0xc                    @ encoding: [0xbf,0xf3,0x5c,0x8f]
 @ CHECK: dmb  ish                     @ encoding: [0xbf,0xf3,0x5b,0x8f]
 @ CHECK: dmb  ishst                   @ encoding: [0xbf,0xf3,0x5a,0x8f]
 @ CHECK: dmb  #0x9                    @ encoding: [0xbf,0xf3,0x59,0x8f]

 @ CHECK: dmb  ishst                   @ encoding: [0xbf,0xf3,0x5a,0x8f]
 @ CHECK: dmb  nsh                     @ encoding: [0xbf,0xf3,0x57,0x8f]
 @ CHECK: dmb  nsh                     @ encoding: [0xbf,0xf3,0x57,0x8f]
 @ CHECK: dmb  nshst                   @ encoding: [0xbf,0xf3,0x56,0x8f]
 @ CHECK: dmb  nshst                   @ encoding: [0xbf,0xf3,0x56,0x8f]
 @ CHECK: dmb  osh                     @ encoding: [0xbf,0xf3,0x53,0x8f]
 @ CHECK: dmb  oshst                   @ encoding: [0xbf,0xf3,0x52,0x8f]
 @ CHECK: dmb  sy                      @ encoding: [0xbf,0xf3,0x5f,0x8f]
+@ CHECK: dmb  sy                      @ encoding: [0xbf,0xf3,0x5f,0x8f]
 
 
 @------------------------------------------------------------------------------
 @ DSB
 @------------------------------------------------------------------------------
         dsb #0xf
         dsb #0xe
         dsb #0xd
@------------------------------------------------------------------------------
         dsb ishst
         dsb un
         dsb nsh
         dsb unst
         dsb nshst
         dsb osh
         dsb oshst
         dsb
+        dsb.w
 
 @ CHECK: dsb  sy                      @ encoding: [0xbf,0xf3,0x4f,0x8f]
 @ CHECK: dsb  st                      @ encoding: [0xbf,0xf3,0x4e,0x8f]
 @ CHECK: dsb  #0xd                    @ encoding: [0xbf,0xf3,0x4d,0x8f]
 @ CHECK: dsb  #0xc                    @ encoding: [0xbf,0xf3,0x4c,0x8f]
 @ CHECK: dsb  ish                     @ encoding: [0xbf,0xf3,0x4b,0x8f]
 @ CHECK: dsb  ishst                   @ encoding: [0xbf,0xf3,0x4a,0x8f]
 @ CHECK: dsb  #0x9                    @ encoding: [0xbf,0xf3,0x49,0x8f]

 @ CHECK: dsb  ishst                   @ encoding: [0xbf,0xf3,0x4a,0x8f]
 @ CHECK: dsb  nsh                     @ encoding: [0xbf,0xf3,0x47,0x8f]
 @ CHECK: dsb  nsh                     @ encoding: [0xbf,0xf3,0x47,0x8f]
 @ CHECK: dsb  nshst                   @ encoding: [0xbf,0xf3,0x46,0x8f]
 @ CHECK: dsb  nshst                   @ encoding: [0xbf,0xf3,0x46,0x8f]
 @ CHECK: dsb  osh                     @ encoding: [0xbf,0xf3,0x43,0x8f]
 @ CHECK: dsb  oshst                   @ encoding: [0xbf,0xf3,0x42,0x8f]
 @ CHECK: dsb  sy                      @ encoding: [0xbf,0xf3,0x4f,0x8f]
+@ CHECK: dsb  sy                      @ encoding: [0xbf,0xf3,0x4f,0x8f]
 
 
 @------------------------------------------------------------------------------
 @ EOR
 @------------------------------------------------------------------------------
         eor r4, r5, #0xf000
         eor r4, r5, r6
         eor r4, r5, r6, lsl #5

 @ CHECK: eor.w  r4, r5, r6, ror #5      @ encoding: [0x85,0xea,0x76,0x14]
 
 
 @------------------------------------------------------------------------------
 @ ISB
 @------------------------------------------------------------------------------
         isb sy
         isb
+        isb.w
         isb #15
         isb #1
 
 @ CHECK: isb  sy                      @ encoding: [0xbf,0xf3,0x6f,0x8f]
 @ CHECK: isb  sy                      @ encoding: [0xbf,0xf3,0x6f,0x8f]
 @ CHECK: isb  sy                      @ encoding: [0xbf,0xf3,0x6f,0x8f]
+@ CHECK: isb  sy                      @ encoding: [0xbf,0xf3,0x6f,0x8f]
 @ CHECK: isb  #0x1                    @ encoding: [0xbf,0xf3,0x61,0x8f]
 
 
 @------------------------------------------------------------------------------
 @ IT
 @------------------------------------------------------------------------------
 @ Test encodings of a few full IT blocks, not just the IT instruction