add cdpair() for AArch64 (dlang#21466)

Author: WalterBright

compiler/src/dmd/backend/arm/cod1.d

@@ -470,7 +470,7 @@ void loadea(ref CodeBuilder cdb,elem* e,ref code cs,uint op,reg_t reg,targ_size_
     debug
     if (debugw)
         printf("loadea: e=%p cs=%p op=x%x reg=%s offset=%lld keepmsk=%s desmsk=%s\n",
-               e, &cs, op, regstring[reg], cast(ulong)offset, regm_str(keepmsk), regm_str(desmsk));
+               e, &cs, op, regm_str(mask(reg)), cast(ulong)offset, regm_str(keepmsk), regm_str(desmsk));
     assert(e);
     cs.Iflags = 0;
     cs.Iop = op;
@@ -2466,9 +2466,9 @@ void loaddata(ref CodeBuilder cdb, elem* e, ref regm_t outretregs)
         }
         else if (sz <= 2 * REGSIZE)
         {
-            reg = findregmsw(forregs);
+            reg = findreg(forregs & INSTR.MSW);
             loadea(cdb, e, cs, 0x8B, reg, REGSIZE, forregs, 0); // MOV reg,data+2
-            reg = findreglsw(forregs);
+            reg = findreg(forregs & INSTR.LSW);
             loadea(cdb, e, cs, 0x8B, reg, 0, forregs, 0);       // MOV reg,data
         }
         else if (sz >= 8)

compiler/src/dmd/backend/arm/cod2.d

@@ -209,6 +209,7 @@ Extend tyToExtend(tym_t ty)
         case 1: extend = UXTB; break;
         case 2: extend = UXTH; break;
         case 4: extend = UXTW; break;
+        case 16:               // in case TYucent for OPpair/OPrpair
         case 8: extend = LSL;  break;
         default:
             assert(0);

compiler/src/dmd/backend/arm/cod4.d

@@ -1899,7 +1899,7 @@ void cdlngsht(ref CGstate cg, ref CodeBuilder cdb,elem* e,ref regm_t pretregs)
             codelem(cgstate,cdb,e.E1,retregs,false);
             bool isOff = e.Eoper == OPoffset;
             if (isOff || e.Eoper == OP128_64)
-                retregs &= mLSW;                // want LSW only
+                retregs &= INSTR.LSW;                // want LSW only
         }
     }
 
@@ -2012,7 +2012,48 @@ void cdpopcnt(ref CGstate cg, ref CodeBuilder cdb,elem* e,ref regm_t pretregs)
     fixresult(cdb,e,retregs,pretregs);
 }
 
-// cdpair
+/*******************************************
+ * Generate code for OPpair, OPrpair.
+ */
+@trusted
+void cdpair(ref CGstate cg, ref CodeBuilder cdb, elem* e, ref regm_t pretregs)
+{
+    assert(pretregs);
+
+    //printf("cdpair(e = %p, pretregs = %s)\n", e, regm_str(pretregs));
+    //elem_print(e);
+
+    regm_t retregs = pretregs;
+
+    regm_t regs1;
+    regm_t regs2;
+
+    retregs &= cgstate.allregs | INSTR.FLOATREGS;
+    if  (!retregs)
+        retregs = cgstate.allregs | INSTR.FLOATREGS;
+    regs1 = retregs & INSTR.LSW;
+    regs2 = retregs & INSTR.MSW;
+
+    if (e.Eoper == OPrpair)
+    {
+        // swap
+        regs1 ^= regs2;
+        regs2 ^= regs1;
+        regs1 ^= regs2;
+    }
+    //printf("1: regs1 = %s, regs2 = %s\n", regm_str(regs1), regm_str(regs2));
+
+    codelem(cgstate,cdb,e.E1, regs1, false);
+    scodelem(cgstate,cdb,e.E2, regs2, regs1, false);
+
+    if (e.E1.Ecount)
+        getregs(cdb,regs1);
+    if (e.E2.Ecount)
+        getregs(cdb,regs2);
+
+    fixresult(cdb,e,regs1 | regs2,pretregs);
+}
+
 // cdcmpxchg
 // cdprefetch
 // opAssLoadReg

compiler/src/dmd/backend/arm/instr.d

@@ -45,6 +45,11 @@ struct INSTR
     enum FLOATREGS = 0x01FF_FFFF_0000_0000;
     static assert((FLOATREGS & (1UL << 57 /*REGMAX*/)) == 0);
 
+    /* most and least significant register masks
+     */
+    enum LSW = 0x5555_5555_5555_5555;
+    enum MSW = LSW << 1;
+
     enum uint nop = 0xD503201F;
 
     alias reg_t = ubyte;

compiler/src/dmd/backend/x86/cod4.d

@@ -4658,10 +4658,14 @@ void cdpair(ref CGstate cg, ref CodeBuilder cdb, elem* e, ref regm_t pretregs)
         return;
     }
 
-    assert(!cg.AArch64);
-    //printf("\ncdpair(e = %p, pretregs = %s)\n", e, regm_str(pretregs));
-    //WRTYxx(e.Ety);printf("\n");
-    //printf("Ecount = %d\n", e.Ecount);
+    if (cg.AArch64)
+    {
+        import dmd.backend.arm.cod4 : cdpair;
+        return cdpair(cg, cdb, e, pretregs);
+    }
+
+    //printf("cdpair(e = %p, pretregs = %s)\n", e, regm_str(pretregs));
+    //elem_print(e);
 
     regm_t retregs = pretregs;
     if (retregs == mPSW && tycomplex(e.Ety) && config.inline8087)