[flang-commits] [flang] [flang] Skip over fixed form spaces when prescanning exponents & kind… (PR #145347)

[Peter Klausler via flang-commits]

https://github.com/klausler created https://github.com/llvm/llvm-project/pull/145347

… suffixes

When performing conditional tokenization of exponents and numeric kind suffixes, be sure to skip over spaces in fixed form source.

Fixes https://github.com/llvm/llvm-project/issues/145333.

>From 521c61a648869c50ae8ef292609887163e7661db Mon Sep 17 00:00:00 2001
From: Peter Klausler <pklausler at nvidia.com>
Date: Mon, 23 Jun 2025 08:52:52 -0700
Subject: [PATCH] [flang] Skip over fixed form spaces when prescanning
 exponents & kind suffixes

When performing conditional tokenization of exponents and numeric
kind suffixes, be sure to skip over spaces in fixed form source.

Fixes https://github.com/llvm/llvm-project/issues/145333.
---
 flang/lib/Parser/prescan.cpp      | 18 ++++++++++++++++++
 flang/test/Preprocessing/bug518.F |  2 +-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/flang/lib/Parser/prescan.cpp b/flang/lib/Parser/prescan.cpp
index 9aef0c9981e3c..ed5184b0aa13d 100644
--- a/flang/lib/Parser/prescan.cpp
+++ b/flang/lib/Parser/prescan.cpp
@@ -915,12 +915,21 @@ bool Prescanner::HandleExponent(TokenSequence &tokens) {
     int startColumn{column_};
     TokenSequence possible;
     EmitCharAndAdvance(possible, *at_);
+    if (InFixedFormSource()) {
+      SkipSpaces();
+    }
     if (*at_ == '+' || *at_ == '-') {
       EmitCharAndAdvance(possible, *at_);
+      if (InFixedFormSource()) {
+        SkipSpaces();
+      }
     }
     if (IsDecimalDigit(*at_)) { // it's an exponent; scan it
       while (IsDecimalDigit(*at_)) {
         EmitCharAndAdvance(possible, *at_);
+        if (InFixedFormSource()) {
+          SkipSpaces();
+        }
       }
       possible.CloseToken();
       tokens.AppendRange(possible, 0); // appends to current token
@@ -940,13 +949,22 @@ bool Prescanner::HandleKindSuffix(TokenSequence &tokens) {
   TokenSequence withUnderscore, separate;
   EmitChar(withUnderscore, '_');
   EmitCharAndAdvance(separate, '_');
+  if (InFixedFormSource()) {
+    SkipSpaces();
+  }
   if (IsLegalInIdentifier(*at_)) {
     separate.CloseToken();
     EmitChar(withUnderscore, *at_);
     EmitCharAndAdvance(separate, *at_);
+    if (InFixedFormSource()) {
+      SkipSpaces();
+    }
     while (IsLegalInIdentifier(*at_)) {
       EmitChar(withUnderscore, *at_);
       EmitCharAndAdvance(separate, *at_);
+      if (InFixedFormSource()) {
+        SkipSpaces();
+      }
     }
   }
   withUnderscore.CloseToken();
diff --git a/flang/test/Preprocessing/bug518.F b/flang/test/Preprocessing/bug518.F
index 0b680dd5751b9..beb33564e4232 100644
--- a/flang/test/Preprocessing/bug518.F
+++ b/flang/test/Preprocessing/bug518.F
@@ -1,5 +1,5 @@
 ! RUN: %flang_fc1 -fdebug-unparse %s 2>&1 | FileCheck %s
 ! CHECK: k=1_4
                         k=                                            1_99999999
-     &4
+     & 4
       end