diff --git a/.pick_status.json b/.pick_status.json
index f28b9fbf360..63f5ce3c9cb 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -3094,7 +3094,7 @@
         "description": "glcpp: fix paste within macro function expansion",
         "nominated": true,
         "nomination_type": 2,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "d5cd40343f4a83d3270cb87ef38e85dcb9682e8c",
         "notes": null
diff --git a/src/compiler/glsl/glcpp/glcpp-parse.y b/src/compiler/glsl/glcpp/glcpp-parse.y
index e6758a6ab98..459856ddef1 100644
--- a/src/compiler/glsl/glcpp/glcpp-parse.y
+++ b/src/compiler/glsl/glcpp/glcpp-parse.y
@@ -1930,6 +1930,7 @@ _glcpp_parser_expand_function(glcpp_parser_t *parser, token_node_t *node,
    /* Perform argument substitution on the replacement list. */
    substituted = _token_list_create(parser);
 
+   bool prev_paste_token = false;
    for (node = macro->replacements->head; node; node = node->next) {
       if (node->token->type == IDENTIFIER &&
           _string_list_contains(macro->parameters, node->token->value.str,
@@ -1941,7 +1942,26 @@ _glcpp_parser_expand_function(glcpp_parser_t *parser, token_node_t *node,
          if (argument->head) {
             token_list_t *expanded_argument;
             expanded_argument = _token_list_copy(parser, argument);
-            _glcpp_parser_expand_token_list(parser, expanded_argument, mode);
+
+            /* From the C99 spec Section 10.3.1 (Argument substitution):
+             *    "After the arguments for the invocation of a function-like
+             *    macro have been identified, argument substitution takes
+             *    place. A parameter in the replacement list, unless preceded
+             *    by a # or ## preprocessing token or followed by a ##
+             *    preprocessing token (see below), is replaced by the
+             *    corresponding argument after all macros contained therein
+             *    have been expanded."
+             */
+
+            /* Look ahead for a PASTE token, skipping space. */
+            token_node_t *next_non_space = node->next;
+            while (next_non_space && next_non_space->token->type == SPACE)
+               next_non_space = next_non_space->next;
+
+            if (!prev_paste_token &&
+                (!next_non_space || next_non_space->token->type != PASTE))
+               _glcpp_parser_expand_token_list(parser, expanded_argument, mode);
+
             _token_list_append_list(substituted, expanded_argument);
          } else {
             token_t *new_token;
@@ -1953,6 +1973,9 @@ _glcpp_parser_expand_function(glcpp_parser_t *parser, token_node_t *node,
       } else {
          _token_list_append(parser, substituted, node->token);
       }
+
+      if (node->token->type != SPACE)
+         prev_paste_token = node->token->type == PASTE;
    }
 
    /* After argument substitution, and before further expansion
diff --git a/src/compiler/glsl/glcpp/tests/114-paste-integer-tokens.c.expected b/src/compiler/glsl/glcpp/tests/114-paste-integer-tokens.c.expected
index 5bc14befa67..45f2115491a 100644
--- a/src/compiler/glsl/glcpp/tests/114-paste-integer-tokens.c.expected
+++ b/src/compiler/glsl/glcpp/tests/114-paste-integer-tokens.c.expected
@@ -1,7 +1,7 @@
 
 
 
-4. HTTP code for Not Found: 404
-5. Hexadecimal for 20560: 5050
-6: Zip code for Nortonville, KS: 66060
-7. James Bond, as a number: 007
+4. HTTP code for Not Found: __LINE____FILE____LINE__
+5. Hexadecimal for 20560: __LINE____FILE____LINE____FILE__
+6: Zip code for Nortonville, KS: __LINE____LINE____FILE____LINE____FILE__
+7. James Bond, as a number: __FILE____FILE____LINE__
diff --git a/src/compiler/glsl/glcpp/tests/150-token-accidental-concatenation.c b/src/compiler/glsl/glcpp/tests/150-token-accidental-concatenation.c
index 9e061b68a8c..ae85bebb2af 100644
--- a/src/compiler/glsl/glcpp/tests/150-token-accidental-concatenation.c
+++ b/src/compiler/glsl/glcpp/tests/150-token-accidental-concatenation.c
@@ -12,5 +12,5 @@ A(r, s)
 B(r, s)
 C(r)s
 A(a, b)
-//B(a, b) // not working yet; gcc and clang give `ab`, we give `xaxb`
+B(a, b)
 C(a)b
diff --git a/src/compiler/glsl/glcpp/tests/150-token-accidental-concatenation.c.expected b/src/compiler/glsl/glcpp/tests/150-token-accidental-concatenation.c.expected
index cdaf5949732..bb1a9326308 100644
--- a/src/compiler/glsl/glcpp/tests/150-token-accidental-concatenation.c.expected
+++ b/src/compiler/glsl/glcpp/tests/150-token-accidental-concatenation.c.expected
@@ -12,5 +12,5 @@ r s
 rs
 r s
 xa xb
-
+ab
 xa xb