diff --git a/Test/baseResults/hlsl.pp.expand.frag.out b/Test/baseResults/hlsl.pp.expand.frag.out
index adfe02c12..97df910ad 100644
--- a/Test/baseResults/hlsl.pp.expand.frag.out
+++ b/Test/baseResults/hlsl.pp.expand.frag.out
@@ -9,7 +9,7 @@ struct A
     float4 a;
     float4 b;
     float4 c = { 1, 2, 3, 4 };
-    float4 d = {({ {(({ 1, 2, 3, 4 }))} })}, { { 1, 2, 3, 4 } };
+    float4 d = { ({ { ( ({ 1, 2, 3, 4 })) } }) }, { { 1, 2, 3, 4 } };
 };
 
 void main()
diff --git a/Test/baseResults/preprocessor.edge_cases.vert.out b/Test/baseResults/preprocessor.edge_cases.vert.out
index 17d9049bf..6a4ad4a7e 100644
--- a/Test/baseResults/preprocessor.edge_cases.vert.out
+++ b/Test/baseResults/preprocessor.edge_cases.vert.out
@@ -10,7 +10,7 @@
 
 
 
-void main(){
+void main() {
   gl_Position = vec4(3 + 2 + 2 * 4 + 2 + 3 * 2);
 }
 
diff --git a/Test/baseResults/preprocessor.extensions.vert.out b/Test/baseResults/preprocessor.extensions.vert.out
index 57d2e199f..59c6e8567 100644
--- a/Test/baseResults/preprocessor.extensions.vert.out
+++ b/Test/baseResults/preprocessor.extensions.vert.out
@@ -7,6 +7,6 @@
 
 #extension unknown_extension : require
 
-int main(){
+int main() {
 }
 
diff --git a/Test/baseResults/preprocessor.function_macro.vert.out b/Test/baseResults/preprocessor.function_macro.vert.out
index 010251e0c..84b0a8727 100644
--- a/Test/baseResults/preprocessor.function_macro.vert.out
+++ b/Test/baseResults/preprocessor.function_macro.vert.out
@@ -15,10 +15,10 @@
 
 
 
-int main(){
+int main() {
   gl_Position = vec4(3 + 1, 3 + 4, 3 + 1);
   gl_Position = vec4(1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12);
   gl_Position = vec4(4 + 3 + 3);
-  gl_Position = 4 + 3 + F . a;
+  gl_Position = 4 + 3 + F.a;
 }
 
diff --git a/Test/baseResults/preprocessor.line.frag.out b/Test/baseResults/preprocessor.line.frag.out
index 3e2206f88..76877943c 100644
--- a/Test/baseResults/preprocessor.line.frag.out
+++ b/Test/baseResults/preprocessor.line.frag.out
@@ -1,5 +1,5 @@
 #version 310 es
 #line 1 2
 #pragma something
-void main(){ }
+void main() { }
 
diff --git a/Test/baseResults/preprocessor.line.vert.out b/Test/baseResults/preprocessor.line.vert.out
index 2bf090327..fbd851cb2 100644
--- a/Test/baseResults/preprocessor.line.vert.out
+++ b/Test/baseResults/preprocessor.line.vert.out
@@ -23,7 +23,7 @@
 
 #line 8
 
-void main(){
+void main() {
   gl_Position = vec4(10);
 }
 
diff --git a/Test/baseResults/preprocessor.pragma.vert.out b/Test/baseResults/preprocessor.pragma.vert.out
index ebe1e4a74..8fa3d338d 100644
--- a/Test/baseResults/preprocessor.pragma.vert.out
+++ b/Test/baseResults/preprocessor.pragma.vert.out
@@ -9,6 +9,6 @@
 
 #pragma once
 
-int main(){
+int main() {
 }
 
diff --git a/Test/baseResults/preprocessor.simple.vert.out b/Test/baseResults/preprocessor.simple.vert.out
index 57b020c67..b54e0a004 100644
--- a/Test/baseResults/preprocessor.simple.vert.out
+++ b/Test/baseResults/preprocessor.simple.vert.out
@@ -11,15 +11,15 @@
 
 
 
-             float fn(float x){ return x + 4.0;}
+             float fn(float x) { return x + 4.0; }
 
-int main(){
+int main() {
   gl_Position = vec4(1);
   gl_Position = clamp(1, 2, 3);
   gl_Position = vec4(1);
   gl_Position = vec4(1, 2);
   gl_Position = vec4(fn(3));
-  []. ++ --
+  [].++ --
   + - * % / - ! ~
   << >> < > <= >=
   == !=
@@ -46,16 +46,21 @@ struct S {
 
 
 
+void bar(int x) { }
+
 void foo()
 {
     S s;
-    s . member2 + s . member1;
-    s . member3 . zyx;
-    s . member2 . xxyz;
-    s . member2 . yyz;
-    s . member2 . xxyz();
-    s . member2 . yzy;
-            vec3 a = vec3(0);vec3 b = a . zxyz;vec3 b = a . xxyz;vec3 b = a . yyz;vec3 b = a . xxyz();vec3 b = a . yzy;vec3 b = a . z;
+    s.member2 + s.member1;
+    s.member3.zyx;
+    s.member2.xxyz;
+    s.member2.yyz;
+    s.member2.xxyz();
+    s.member2.yzy;
+    for (int i = 0; i < 100; i = i + 1) {
+      bar(i)
+    }
+            vec3 a = vec3(0); vec3 b = a.zxyz; vec3 b = a.xxyz; vec3 b = a.yyz; vec3 b = a.xxyz(); vec3 b = a.yzy; vec3 b = a.z;
 
 
      yyz;
diff --git a/Test/baseResults/preprocessor.success_if_parse_would_fail.vert.out b/Test/baseResults/preprocessor.success_if_parse_would_fail.vert.out
index 624813a01..ed1ad0c0e 100644
--- a/Test/baseResults/preprocessor.success_if_parse_would_fail.vert.out
+++ b/Test/baseResults/preprocessor.success_if_parse_would_fail.vert.out
@@ -1,4 +1,4 @@
-int x(){
+int x() {
   something that shouldnt compile;
 }
 
diff --git a/Test/preprocessor.simple.vert b/Test/preprocessor.simple.vert
index 788df76ce..6c4485008 100644
--- a/Test/preprocessor.simple.vert
+++ b/Test/preprocessor.simple.vert
@@ -46,6 +46,8 @@ struct S {
 	vec3 b = a.yzy;   \
 	vec3 b = a.z;
 
+void bar(int x) {}
+
 void foo()
 {
     S s;
@@ -55,6 +57,9 @@ void foo()
     s.member2.yzy();
     s.member2.xyz();
     s.member2.yzy;
+    for(int i = 0;i < 100; i = i + 1) {
+      bar (i)
+    }
     FUN_MAC()
     yzy
 
diff --git a/glslang/MachineIndependent/ShaderLang.cpp b/glslang/MachineIndependent/ShaderLang.cpp
index 2c77e2fd2..9a42acae9 100644
--- a/glslang/MachineIndependent/ShaderLang.cpp
+++ b/glslang/MachineIndependent/ShaderLang.cpp
@@ -1068,8 +1068,8 @@ struct DoPreprocessing {
                     EShOptimizationLevel, EShMessages)
     {
         // This is a list of tokens that do not require a space before or after.
-        static const std::string unNeededSpaceTokens = ";()[]";
-        static const std::string noSpaceBeforeTokens = ",";
+        static const std::string noNeededSpaceBeforeTokens = ";)[].,";
+        static const std::string noNeededSpaceAfterTokens = ".([";
         glslang::TPpToken ppToken;
 
         parseContext.setScanner(&input);
@@ -1142,6 +1142,7 @@ struct DoPreprocessing {
         });
 
         int lastToken = EndOfInput; // lastToken records the last token processed.
+        std::string lastTokenName;
         do {
             int token = ppContext.tokenize(ppToken);
             if (token == EndOfInput)
@@ -1160,12 +1161,23 @@ struct DoPreprocessing {
             // Output a space in between tokens, but not at the start of a line,
             // and also not around special tokens. This helps with readability
             // and consistency.
-            if (!isNewString && !isNewLine && lastToken != EndOfInput &&
-                (unNeededSpaceTokens.find((char)token) == std::string::npos) &&
-                (unNeededSpaceTokens.find((char)lastToken) == std::string::npos) &&
-                (noSpaceBeforeTokens.find((char)token) == std::string::npos)) {
-                outputBuffer += ' ';
+            if (!isNewString && !isNewLine && lastToken != EndOfInput) {
+                // left parenthesis need a leading space, except it is in a function-call-like context.
+                // examples: `for (xxx)`, `a * (b + c)`, `vec(2.0)`, `foo(x, y, z)`
+                if (token == '(') {
+                    if (lastToken != PpAtomIdentifier ||
+                        lastTokenName == "if" ||
+                        lastTokenName == "for" ||
+                        lastTokenName == "while" ||
+                        lastTokenName == "switch")
+                        outputBuffer += ' ';
+                } else if ((noNeededSpaceBeforeTokens.find((char)token) == std::string::npos) &&
+                    (noNeededSpaceAfterTokens.find((char)lastToken) == std::string::npos)) {
+                    outputBuffer += ' ';
+                }
             }
+            if (token == PpAtomIdentifier)
+                lastTokenName = ppToken.name;
             lastToken = token;
             if (token == PpAtomConstString)
                 outputBuffer += "\"";