| Message ID | 2045800.G86V45WoCa@polaris |
|---|---|
| State | New |
| Headers | show |
| Series | [rs6000] Do not generate sibling call to nested function | expand |
Hi! On Mon, Sep 17, 2018 at 11:11:53AM +0200, Eric Botcazou wrote: > more precisely, to a nested function that requires a static chain. The reason > is that the sibling call epilogue may clobber the static chain register r11. > > Tested on PowerPC/Linux, OK for the mainline? > > > 2018-09-17 Eric Botcazou <ebotcazou@adacore.com> > > * config/rs6000/rs6000.c (rs6000_function_ok_for_sibcall): Return false > if the call takes a static chain. > --- config/rs6000/rs6000.c (revision 264342) > +++ config/rs6000/rs6000.c (working copy) > @@ -24332,6 +24332,10 @@ rs6000_function_ok_for_sibcall (tree dec > { > tree fntype; > > + /* The sibcall epilogue may clobber the static chain register. */ > + if (CALL_EXPR_STATIC_CHAIN (exp)) > + return false; > + > if (decl) > fntype = TREE_TYPE (decl); > else We could probably make sibcalls work with static chain, but that is most likely not worth it. Could you change the comment to say something like that? Approved for trunk and backports. Thanks! Segher
Hi Eric, On 18/09/18 15:56, Segher Boessenkool wrote: > Hi! > > On Mon, Sep 17, 2018 at 11:11:53AM +0200, Eric Botcazou wrote: > > more precisely, to a nested function that requires a static chain. The reason > > is that the sibling call epilogue may clobber the static chain register r11. > > > > Tested on PowerPC/Linux, OK for the mainline? > > > > > > 2018-09-17 Eric Botcazou <ebotcazou@adacore.com> > > > > * config/rs6000/rs6000.c (rs6000_function_ok_for_sibcall): Return false > > if the call takes a static chain. > > > > --- config/rs6000/rs6000.c (revision 264342) > > +++ config/rs6000/rs6000.c (working copy) > > @@ -24332,6 +24332,10 @@ rs6000_function_ok_for_sibcall (tree dec > > { > > tree fntype; > > > > + /* The sibcall epilogue may clobber the static chain register. */ > > + if (CALL_EXPR_STATIC_CHAIN (exp)) > > + return false; > > + > > if (decl) > > fntype = TREE_TYPE (decl); > > else > > We could probably make sibcalls work with static chain, but that is most > likely not worth it. Could you change the comment to say something like > that? > > Approved for trunk and backports. Thanks! > I'm seeing a testism on the GCC 7 branch due to the noipa attribute in the testcase. I think it doesn't exist in GCC 7 so we're getting a test for excess errors FAIL: warning: 'noipa' attribute directive ignored [-Wattributes] Any chance we can adjust the testcase? Thanks, Kyrill > > Segher
> I'm seeing a testism on the GCC 7 branch due to the noipa attribute in the > testcase. I think it doesn't exist in GCC 7 so we're getting a test for > excess errors FAIL: > > warning: 'noipa' attribute directive ignored [-Wattributes] > > Any chance we can adjust the testcase? Yes, I did it yesterday.
Index: config/rs6000/rs6000.c =================================================================== --- config/rs6000/rs6000.c (revision 264342) +++ config/rs6000/rs6000.c (working copy) @@ -24332,6 +24332,10 @@ rs6000_function_ok_for_sibcall (tree dec { tree fntype; + /* The sibcall epilogue may clobber the static chain register. */ + if (CALL_EXPR_STATIC_CHAIN (exp)) + return false; + if (decl) fntype = TREE_TYPE (decl); else