Index: llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
+++ llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
@@ -1438,7 +1438,7 @@
 
   void peekTokens(MutableArrayRef<AsmToken> Tokens);
   AsmToken::TokenKind getTokenKind() const;
-  bool parseExpr(int64_t &Imm);
+  bool parseExpr(int64_t &Imm, StringRef Expected = "");
   bool parseExpr(OperandVector &Operands);
   StringRef getTokenStr() const;
   AsmToken peekToken();
@@ -5673,8 +5673,8 @@
   if (isToken(AsmToken::Identifier) &&
       (HwReg.Id = getHwregId(getTokenStr())) >= 0) {
     HwReg.IsSymbolic = true;
-    lex(); // skip message name
-  } else if (!parseExpr(HwReg.Id)) {
+    lex(); // skip register name
+  } else if (!parseExpr(HwReg.Id, "a register name")) {
     return false;
   }
 
@@ -5743,7 +5743,7 @@
     } else {
       return MatchOperand_ParseFail;
     }
-  } else if (parseExpr(ImmVal)) {
+  } else if (parseExpr(ImmVal, "an hwreg macro")) {
     if (ImmVal < 0 || !isUInt<16>(ImmVal)) {
       Error(Loc, "invalid immediate: only 16-bit values are legal");
       return MatchOperand_ParseFail;
@@ -5774,7 +5774,7 @@
   if (isToken(AsmToken::Identifier) && (Msg.Id = getMsgId(getTokenStr())) >= 0) {
     Msg.IsSymbolic = true;
     lex(); // skip message name
-  } else if (!parseExpr(Msg.Id)) {
+  } else if (!parseExpr(Msg.Id, "a message name")) {
     return false;
   }
 
@@ -5784,7 +5784,7 @@
     if (isToken(AsmToken::Identifier) &&
         (Op.Id = getMsgOpId(Msg.Id, getTokenStr())) >= 0) {
       lex(); // skip operation name
-    } else if (!parseExpr(Op.Id)) {
+    } else if (!parseExpr(Op.Id, "an operation name")) {
       return false;
     }
 
@@ -5854,7 +5854,7 @@
     } else {
       return MatchOperand_ParseFail;
     }
-  } else if (parseExpr(ImmVal)) {
+  } else if (parseExpr(ImmVal, "a sendmsg macro")) {
     if (ImmVal < 0 || !isUInt<16>(ImmVal)) {
       Error(Loc, "invalid immediate: only 16-bit values are legal");
       return MatchOperand_ParseFail;
@@ -6072,8 +6072,23 @@
 }
 
 bool
-AMDGPUAsmParser::parseExpr(int64_t &Imm) {
-  return !getParser().parseAbsoluteExpression(Imm);
+AMDGPUAsmParser::parseExpr(int64_t &Imm, StringRef Expected) {
+  SMLoc S = getLoc();
+
+  const MCExpr *Expr;
+  if (Parser.parseExpression(Expr))
+    return false;
+
+  if (Expr->evaluateAsAbsolute(Imm))
+    return true;
+
+  if (Expected.empty()) {
+    Error(S, "expected absolute expression");
+  } else {
+    Error(S, Twine("expected ", Expected) +
+             Twine(" or an absolute expression"));
+  }
+  return false;
 }
 
 bool
@@ -6390,7 +6405,7 @@
 
   SMLoc OffsetLoc = Parser.getTok().getLoc();
 
-  if (!parseExpr(Imm)) {
+  if (!parseExpr(Imm, "a swizzle macro")) {
     return false;
   }
   if (!isUInt<16>(Imm)) {
Index: llvm/test/MC/AMDGPU/ds-err.s
===================================================================
--- llvm/test/MC/AMDGPU/ds-err.s
+++ llvm/test/MC/AMDGPU/ds-err.s
@@ -46,7 +46,7 @@
 // CHECK: error: expected a colon
 ds_swizzle_b32 v8, v2 offset-
 
-// CHECK: error: expected absolute expression
+// CHECK: error: expected a swizzle macro or an absolute expression
 ds_swizzle_b32 v8, v2 offset:SWIZZLE(QUAD_PERM, 0, 1, 2, 3)
 
 // CHECK: error: expected a swizzle mode
Index: llvm/test/MC/AMDGPU/gfx10_err_pos.s
===================================================================
--- llvm/test/MC/AMDGPU/gfx10_err_pos.s
+++ llvm/test/MC/AMDGPU/gfx10_err_pos.s
@@ -331,26 +331,6 @@
 //==============================================================================
 // expected absolute expression
 
-ds_swizzle_b32 v8, v2 offset:SWIZZLE(QUAD_PERM, 0, 1, 2, 3)
-// CHECK: error: expected absolute expression
-// CHECK-NEXT:{{^}}ds_swizzle_b32 v8, v2 offset:SWIZZLE(QUAD_PERM, 0, 1, 2, 3)
-// CHECK-NEXT:{{^}}                             ^
-
-s_sendmsg sendmsg(MSG_GS, GS_OP_CUTX, 0)
-// CHECK: error: expected absolute expression
-// CHECK-NEXT:{{^}}s_sendmsg sendmsg(MSG_GS, GS_OP_CUTX, 0)
-// CHECK-NEXT:{{^}}                          ^
-
-s_sendmsg sendmsg(MSG_GSX, GS_OP_CUT, 0)
-// CHECK: error: expected absolute expression
-// CHECK-NEXT:{{^}}s_sendmsg sendmsg(MSG_GSX, GS_OP_CUT, 0)
-// CHECK-NEXT:{{^}}                  ^
-
-s_setreg_b32  hwreg(HW_REG_WRONG), s2
-// CHECK: error: expected absolute expression
-// CHECK-NEXT:{{^}}s_setreg_b32  hwreg(HW_REG_WRONG), s2
-// CHECK-NEXT:{{^}}                    ^
-
 s_waitcnt vmcnt(x)
 // CHECK: error: expected absolute expression
 // CHECK-NEXT:{{^}}s_waitcnt vmcnt(x)
@@ -371,6 +351,38 @@
 // CHECK-NEXT:{{^}}tbuffer_store_format_xyzw v[1:4], off, ttmp[4:7], s0 format:BUF_NUM_FORMAT_UINT]
 // CHECK-NEXT:{{^}}                                                            ^
 
+//==============================================================================
+// expected a message name or an absolute expression
+
+s_sendmsg sendmsg(MSG_GSX, GS_OP_CUT, 0)
+// CHECK: error: expected a message name or an absolute expression
+// CHECK-NEXT:{{^}}s_sendmsg sendmsg(MSG_GSX, GS_OP_CUT, 0)
+// CHECK-NEXT:{{^}}                  ^
+
+//==============================================================================
+// expected a register name or an absolute expression
+
+s_setreg_b32  hwreg(HW_REG_WRONG), s2
+// CHECK: error: expected a register name or an absolute expression
+// CHECK-NEXT:{{^}}s_setreg_b32  hwreg(HW_REG_WRONG), s2
+// CHECK-NEXT:{{^}}                    ^
+
+//==============================================================================
+// expected a sendmsg macro or an absolute expression
+
+s_sendmsg undef
+// CHECK: error: expected a sendmsg macro or an absolute expression
+// CHECK-NEXT:{{^}}s_sendmsg undef
+// CHECK-NEXT:{{^}}          ^
+
+//==============================================================================
+// expected a swizzle macro or an absolute expression
+
+ds_swizzle_b32 v8, v2 offset:SWZ(QUAD_PERM, 0, 1, 2, 3)
+// CHECK: error: expected a swizzle macro or an absolute expression
+// CHECK-NEXT:{{^}}ds_swizzle_b32 v8, v2 offset:SWZ(QUAD_PERM, 0, 1, 2, 3)
+// CHECK-NEXT:{{^}}                             ^
+
 //==============================================================================
 // expected an 11-bit unsigned offset
 
@@ -402,6 +414,22 @@
 // CHECK-NEXT:{{^}}v_mov_b32_sdwa v1, sext(u)
 // CHECK-NEXT:{{^}}                        ^
 
+//==============================================================================
+// expected an hwreg macro or an absolute expression
+
+s_setreg_b32 undef, s2
+// CHECK: error: expected an hwreg macro or an absolute expression
+// CHECK-NEXT:{{^}}s_setreg_b32 undef, s2
+// CHECK-NEXT:{{^}}             ^
+
+//==============================================================================
+// expected an operation name or an absolute expression
+
+s_sendmsg sendmsg(MSG_GS, GS_OP_CUTX, 0)
+// CHECK: error: expected an operation name or an absolute expression
+// CHECK-NEXT:{{^}}s_sendmsg sendmsg(MSG_GS, GS_OP_CUTX, 0)
+// CHECK-NEXT:{{^}}                          ^
+
 //==============================================================================
 // failed parsing operand.
 
Index: llvm/test/MC/AMDGPU/sopk-err.s
===================================================================
--- llvm/test/MC/AMDGPU/sopk-err.s
+++ llvm/test/MC/AMDGPU/sopk-err.s
@@ -14,13 +14,13 @@
 // GCN: error: invalid immediate: only 16-bit values are legal
 
 s_setreg_b32  typo(0x40), s2
-// GCN: error: expected absolute expression
+// GCN: error: expected an hwreg macro or an absolute expression
 
 s_setreg_b32  hwreg(0x40), s2
 // GCN: error: invalid code of hardware register: only 6-bit values are legal
 
 s_setreg_b32  hwreg(HW_REG_WRONG), s2
-// GCN: error: expected absolute expression
+// GCN: error: expected a register name or an absolute expression
 
 s_setreg_b32  hwreg(1 2,3), s2
 // GCN: error: expected a comma or a closing parenthesis
Index: llvm/test/MC/AMDGPU/sopp-err.s
===================================================================
--- llvm/test/MC/AMDGPU/sopp-err.s
+++ llvm/test/MC/AMDGPU/sopp-err.s
@@ -8,7 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 s_sendmsg sendmsg(MSG_INTERRUPTX)
-// GCN: error: expected absolute expression
+// GCN: error: expected a message name or an absolute expression
 
 s_sendmsg sendmsg(1 -)
 // GCN: error: unknown token in expression
@@ -26,7 +26,7 @@
 // GCN: error: invalid operation id
 
 s_sendmsg sendmsg(MSG_GS, SYSMSG_OP_ECC_ERR_INTERRUPT)
-// GCN: error: expected absolute expression
+// GCN: error: expected an operation name or an absolute expression
 
 s_sendmsg sendmsg(MSG_GS, 0)
 // GCN: error: invalid operation id
@@ -50,10 +50,10 @@
 // GCN: error: expected a closing parenthesis
 
 s_sendmsg sendmsg(MSG_GSX, GS_OP_CUT, 0)
-// GCN: error: expected absolute expression
+// GCN: error: expected a message name or an absolute expression
 
 s_sendmsg sendmsg(MSG_GS, GS_OP_CUTX, 0)
-// GCN: error: expected absolute expression
+// GCN: error: expected an operation name or an absolute expression
 
 s_sendmsg sendmsg(MSG_GS, 1 -)
 // GCN: error: unknown token in expression