diff --git a/cmd/vet/testdata/asm1.s b/cmd/vet/testdata/asm1.s
index 071ce3c5..3e4fc3aa 100644
--- a/cmd/vet/testdata/asm1.s
+++ b/cmd/vet/testdata/asm1.s
@@ -9,7 +9,7 @@ TEXT ·arg1(SB),0,$0-2
 	MOVB	x+0(FP), AX
 	// MOVB x+0(FP), AX // commented out instructions used to panic
 	MOVB	y+1(FP), BX
-	MOVW	x+0(FP), AX // ERROR "\[amd64\] invalid MOVW of x\+0\(FP\); int8 is 1-byte value"
+	MOVW	x+0(FP), AX // ERROR "\[amd64\] arg1: invalid MOVW of x\+0\(FP\); int8 is 1-byte value"
 	MOVW	y+1(FP), AX // ERROR "invalid MOVW of y\+1\(FP\); uint8 is 1-byte value"
 	MOVL	x+0(FP), AX // ERROR "invalid MOVL of x\+0\(FP\); int8 is 1-byte value"
 	MOVL	y+1(FP), AX // ERROR "invalid MOVL of y\+1\(FP\); uint8 is 1-byte value"
@@ -30,7 +30,7 @@ TEXT ·arg1(SB),0,$0-2
 	RET
 
 TEXT ·arg2(SB),0,$0-4
-	MOVB	x+0(FP), AX // ERROR "invalid MOVB of x\+0\(FP\); int16 is 2-byte value"
+	MOVB	x+0(FP), AX // ERROR "arg2: invalid MOVB of x\+0\(FP\); int16 is 2-byte value"
 	MOVB	y+2(FP), AX // ERROR "invalid MOVB of y\+2\(FP\); uint16 is 2-byte value"
 	MOVW	x+0(FP), AX
 	MOVW	y+2(FP), BX
@@ -52,7 +52,7 @@ TEXT ·arg2(SB),0,$0-4
 	TESTW	y+0(FP), AX // ERROR "invalid offset y\+0\(FP\); expected y\+2\(FP\)"
 	RET
 
-TEXT ·arg4(SB),0,$0-2 // ERROR "wrong argument size 2; expected \$\.\.\.-8"
+TEXT ·arg4(SB),0,$0-2 // ERROR "arg4: wrong argument size 2; expected \$\.\.\.-8"
 	MOVB	x+0(FP), AX // ERROR "invalid MOVB of x\+0\(FP\); int32 is 4-byte value"
 	MOVB	y+4(FP), BX // ERROR "invalid MOVB of y\+4\(FP\); uint32 is 4-byte value"
 	MOVW	x+0(FP), AX // ERROR "invalid MOVW of x\+0\(FP\); int32 is 4-byte value"
diff --git a/cmd/vet/testdata/asm2.s b/cmd/vet/testdata/asm2.s
index d8679c57..670f54fb 100644
--- a/cmd/vet/testdata/asm2.s
+++ b/cmd/vet/testdata/asm2.s
@@ -8,7 +8,7 @@
 TEXT ·arg1(SB),0,$0-2
 	MOVB	x+0(FP), AX
 	MOVB	y+1(FP), BX
-	MOVW	x+0(FP), AX // ERROR "\[386\] invalid MOVW of x\+0\(FP\); int8 is 1-byte value"
+	MOVW	x+0(FP), AX // ERROR "\[386\] arg1: invalid MOVW of x\+0\(FP\); int8 is 1-byte value"
 	MOVW	y+1(FP), AX // ERROR "invalid MOVW of y\+1\(FP\); uint8 is 1-byte value"
 	MOVL	x+0(FP), AX // ERROR "invalid MOVL of x\+0\(FP\); int8 is 1-byte value"
 	MOVL	y+1(FP), AX // ERROR "invalid MOVL of y\+1\(FP\); uint8 is 1-byte value"
@@ -29,7 +29,7 @@ TEXT ·arg1(SB),0,$0-2
 	RET
 
 TEXT ·arg2(SB),0,$0-4
-	MOVB	x+0(FP), AX // ERROR "invalid MOVB of x\+0\(FP\); int16 is 2-byte value"
+	MOVB	x+0(FP), AX // ERROR "arg2: invalid MOVB of x\+0\(FP\); int16 is 2-byte value"
 	MOVB	y+2(FP), AX // ERROR "invalid MOVB of y\+2\(FP\); uint16 is 2-byte value"
 	MOVW	x+0(FP), AX
 	MOVW	y+2(FP), BX
@@ -51,7 +51,7 @@ TEXT ·arg2(SB),0,$0-4
 	TESTW	y+0(FP), AX // ERROR "invalid offset y\+0\(FP\); expected y\+2\(FP\)"
 	RET
 
-TEXT ·arg4(SB),0,$0-2 // ERROR "wrong argument size 2; expected \$\.\.\.-8"
+TEXT ·arg4(SB),0,$0-2 // ERROR "arg4: wrong argument size 2; expected \$\.\.\.-8"
 	MOVB	x+0(FP), AX // ERROR "invalid MOVB of x\+0\(FP\); int32 is 4-byte value"
 	MOVB	y+4(FP), BX // ERROR "invalid MOVB of y\+4\(FP\); uint32 is 4-byte value"
 	MOVW	x+0(FP), AX // ERROR "invalid MOVW of x\+0\(FP\); int32 is 4-byte value"
diff --git a/cmd/vet/testdata/asm3.s b/cmd/vet/testdata/asm3.s
index bf98805a..4c2643b0 100644
--- a/cmd/vet/testdata/asm3.s
+++ b/cmd/vet/testdata/asm3.s
@@ -8,7 +8,7 @@
 TEXT ·arg1(SB),0,$0-2
 	MOVB	x+0(FP), AX
 	MOVB	y+1(FP), BX
-	MOVH	x+0(FP), AX // ERROR "\[arm\] invalid MOVH of x\+0\(FP\); int8 is 1-byte value"
+	MOVH	x+0(FP), AX // ERROR "\[arm\] arg1: invalid MOVH of x\+0\(FP\); int8 is 1-byte value"
 	MOVH	y+1(FP), AX // ERROR "invalid MOVH of y\+1\(FP\); uint8 is 1-byte value"
 	MOVW	x+0(FP), AX // ERROR "invalid MOVW of x\+0\(FP\); int8 is 1-byte value"
 	MOVW	y+1(FP), AX // ERROR "invalid MOVW of y\+1\(FP\); uint8 is 1-byte value"
@@ -17,7 +17,7 @@ TEXT ·arg1(SB),0,$0-2
 	RET
 
 TEXT ·arg2(SB),0,$0-4
-	MOVB	x+0(FP), AX // ERROR "invalid MOVB of x\+0\(FP\); int16 is 2-byte value"
+	MOVB	x+0(FP), AX // ERROR "arg2: invalid MOVB of x\+0\(FP\); int16 is 2-byte value"
 	MOVB	y+2(FP), AX // ERROR "invalid MOVB of y\+2\(FP\); uint16 is 2-byte value"
 	MOVH	x+0(FP), AX
 	MOVH	y+2(FP), BX
@@ -27,7 +27,7 @@ TEXT ·arg2(SB),0,$0-4
 	MOVH	y+0(FP), AX // ERROR "invalid offset y\+0\(FP\); expected y\+2\(FP\)"
 	RET
 
-TEXT ·arg4(SB),0,$0-2 // ERROR "wrong argument size 2; expected \$\.\.\.-8"
+TEXT ·arg4(SB),0,$0-2 // ERROR "arg4: wrong argument size 2; expected \$\.\.\.-8"
 	MOVB	x+0(FP), AX // ERROR "invalid MOVB of x\+0\(FP\); int32 is 4-byte value"
 	MOVB	y+4(FP), BX // ERROR "invalid MOVB of y\+4\(FP\); uint32 is 4-byte value"
 	MOVH	x+0(FP), AX // ERROR "invalid MOVH of x\+0\(FP\); int32 is 4-byte value"