[SPARC][IAS] Add GNU extension for addc

Transform `addc imm, %rs, %rd` into `addc %rs, imm, %rd`.
This is used in some GNU and Linux code.

Reviewers: s-barannikov, rorth, jrtc27, brad0

Reviewed By: s-barannikov

Pull Request: #94245

Author: koachan

llvm/lib/Target/Sparc/SparcInstrAliases.td

@@ -560,11 +560,16 @@ def : InstAlias<"mov $simm13, %tbr", (WRTBRri G0, simm13Op:$simm13), 0>;
 
 // End of Section A.3
 
-// or imm, reg, rd -> or reg, imm, rd
-// Nonstandard GNU extension.
-let EmitPriority = 0 in
+
+// Nonstandard GNU extensions.
+let EmitPriority = 0 in {
+  // or imm, reg, rd -> or reg, imm, rd
   def : InstAlias<"or $simm13, $rs1, $rd", (ORri IntRegs:$rd, IntRegs:$rs1, simm13Op:$simm13)>;
 
+  // addc/addx imm, reg, rd -> or reg, imm, rd
+  def : InstAlias<"addx $simm13, $rs1, $rd", (ADDCri IntRegs:$rd, IntRegs:$rs1, simm13Op:$simm13)>;
+}
+
 // wr reg_or_imm, specialreg -> wr %g0, reg_or_imm, specialreg
 // (aka: omit the first arg when it's g0. This is not in the manual, but is
 // supported by gnu and solaris as)

llvm/test/MC/Sparc/sparcv9-instructions.s

@@ -6,6 +6,16 @@
         ! V9:      addx %g2, %g1, %g3              ! encoding: [0x86,0x40,0x80,0x01]
         addc %g2, %g1, %g3
 
+        ! V8:      error: invalid instruction mnemonic
+        ! V8-NEXT: addc %g2, 1, %g3
+        ! V9:      addx %g2, 1, %g3              ! encoding: [0x86,0x40,0xa0,0x01]
+        addc %g2, 1, %g3
+
+        ! V8:      error: invalid instruction mnemonic
+        ! V8-NEXT: addc 1, %g2, %g3
+        ! V9:      addx %g2, 1, %g3              ! encoding: [0x86,0x40,0xa0,0x01]
+        addc 1, %g2, %g3
+
         ! V8:      error: invalid instruction mnemonic
         ! V8-NEXT: addccc %g1, %g2, %g3
         ! V9:      addxcc %g1, %g2, %g3            ! encoding: [0x86,0xc0,0x40,0x02]