[llvm-commits] [llvm] r123297 - /llvm/trunk/lib/Target/ARM/ARMMCCodeEmitter.cpp

[Chris Lattner]

On Jan 11, 2011, at 6:13 PM, Nick Lewycky wrote:

> On 11 January 2011 17:47, Chris Lattner <clattner at apple.com> wrote:
> 
> On Jan 11, 2011, at 5:42 PM, Matt Beaumont-Gay wrote:
> 
> > Author: matthewbg
> > Date: Tue Jan 11 19:42:42 2011
> > New Revision: 123297
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=123297&view=rev
> > Log:
> > Prefer llvm_unreachable to assert(0)
> 
> Hi Matt,
> 
> Please use assert(0) unless we need the "does not fallthrough" behavior of llvm_unreachable.
> 
> The difference is that llvm_unreachable still generates code in a Release build while assert() doesn't, right?
> 
> Matt made this commit because we were seeing:
> 
>   llvm/lib/Target/ARM/ARMMCCodeEmitter.cpp:653: error: control reaches end of non-void function [-Wreturn-type]
> 
> so it sounds like llvm_unreachable isn't the right tool, but we'd like to fix this that doesn't generate warnings in release builds.

Please move the default case to the first part of the switch statement:

switch (whatever) {
default:  assert(0 && ...
case 0:

that way, in non-assert builds, the compiler still thinks everything is great.

-Chris

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