[cfe-commits] r148243 - /cfe/trunk/lib/CodeGen/CGStmt.cpp

[Eli Friedman]

On Mon, Jan 16, 2012 at 9:35 AM, Fariborz Jahanian <fjahanian at apple.com> wrote:
> Author: fjahanian
> Date: Mon Jan 16 11:35:57 2012
> New Revision: 148243
>
> URL: http://llvm.org/viewvc/llvm-project?rev=148243&view=rev
> Log:
> Fixes a crash during constant folding of a switch and case
> statement which has an unscoped case inside it.
> Patch by Aaron Ballman
>
> Modified:
>    cfe/trunk/lib/CodeGen/CGStmt.cpp
>
> Modified: cfe/trunk/lib/CodeGen/CGStmt.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGStmt.cpp?rev=148243&r1=148242&r2=148243&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGStmt.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGStmt.cpp Mon Jan 16 11:35:57 2012
> @@ -878,6 +878,16 @@
>  }
>
>  void CodeGenFunction::EmitCaseStmt(const CaseStmt &S) {
> +  // If there is no enclosing switch instance that we're aware of, then this
> +  // case statement and its block can be elided.  This situation only happens
> +  // when we've constant-folded the switch, are emitting the constant case,
> +  // and part of the constant case includes another case statement.  For
> +  // instance: switch (4) { case 4: do { case 5: } while (1); }
> +  if (!SwitchInsn) {
> +    EmitStmt(S.getSubStmt());
> +    return;
> +  }

I'm not convinced that this patch does the right thing if the given
construct is nested into another switch.  Also, testcase?

-Eli