[clang] 19d2c65 - [CodeGen] Don't crash on for loops with cond variables and no increment

[Benjamin Kramer via cfe-commits]

Author: Benjamin Kramer
Date: 2021-03-19T20:43:52+01:00
New Revision: 19d2c65ddd757997785163709800f837857f686d

URL: https://github.com/llvm/llvm-project/commit/19d2c65ddd757997785163709800f837857f686d
DIFF: https://github.com/llvm/llvm-project/commit/19d2c65ddd757997785163709800f837857f686d.diff

LOG: [CodeGen] Don't crash on for loops with cond variables and no increment

This looks like an oversight from a875721d8a2d, creating IR that refers
to `for.inc` even if it doesn't exist.

Differential Revision: https://reviews.llvm.org/D98980

Added: 
    

Modified: 
    clang/lib/CodeGen/CGStmt.cpp
    clang/test/CodeGenCXX/for-cond-var.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 6461e2011216..38f3aa941415 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -992,7 +992,7 @@ void CodeGenFunction::EmitForStmt(const ForStmt &S,
 
       // We have entered the condition variable's scope, so we're now able to
       // jump to the continue block.
-      Continue = getJumpDestInCurrentScope("for.inc");
+      Continue = S.getInc() ? getJumpDestInCurrentScope("for.inc") : CondDest;
       BreakContinueStack.back().ContinueBlock = Continue;
     }
 

diff  --git a/clang/test/CodeGenCXX/for-cond-var.cpp b/clang/test/CodeGenCXX/for-cond-var.cpp
index 45b4a82cb905..60e54d4141f7 100644
--- a/clang/test/CodeGenCXX/for-cond-var.cpp
+++ b/clang/test/CodeGenCXX/for-cond-var.cpp
@@ -123,3 +123,16 @@ void PR49585_break() {
   // CHECK [[for_end]]:
   // CHECK: ret void
 }
+
+// CHECK: define {{.*}} void @_Z16incless_for_loopv(
+void incless_for_loop() {
+  // CHECK: br label %[[for_cond:.*]]
+  // CHECK: [[for_cond]]:
+  // CHECK:   br i1 {{.*}}, label %[[for_body:.*]], label %[[for_end:.*]]
+  // CHECK: [[for_body]]:
+  // CHECK:   br label %[[for_cond]]
+  // CHECK: [[for_end]]:
+  // CHECK:   ret void
+  // CHECK: }
+  for (; int b = 0;) continue;
+}