Since Honza's change in r236012 we're able to expand thunks inline, and as a side-effect we can redirect call within thunk to __buitin_unreachable (at least that's my understanding ;).
But that means we need to employ the maybe_remove_unused_call_args function so that we don't left __buitin_unreachable with arguments in the IL. Bootstrapped/regtested on x86_64-linux, applying to trunk (approved by Honza in the PR). 2016-05-17 Marek Polacek <pola...@redhat.com> PR ipa/71146 * tree-inline.c (expand_call_inline): Call maybe_remove_unused_call_args. * g++.dg/ipa/pr71146.C: New test. diff --git gcc/testsuite/g++.dg/ipa/pr71146.C gcc/testsuite/g++.dg/ipa/pr71146.C index e69de29..54d34a7 100644 --- gcc/testsuite/g++.dg/ipa/pr71146.C +++ gcc/testsuite/g++.dg/ipa/pr71146.C @@ -0,0 +1,29 @@ +// PR ipa/71146 +// { dg-do compile } +// { dg-options "-O3" } + +typedef enum { X } E; +struct A { + virtual void bar (); +}; +struct B { + virtual E fn (const char *, int, int *) = 0; +}; +struct C : A, B { + E fn (const char *, int, int *); + void fn2 (); + B *foo; +}; +void C::fn2 () { + if (!foo) + return; + foo->fn (0, 0, 0); +} +E +C::fn (const char *, int, int *) +{ + fn2 (); + foo = 0; + fn (0, 0, 0); + return X; +} diff --git gcc/tree-inline.c gcc/tree-inline.c index 85ed2c2..954dac3 100644 --- gcc/tree-inline.c +++ gcc/tree-inline.c @@ -4486,6 +4486,7 @@ expand_call_inline (basic_block bb, gimple *stmt, copy_body_data *id) update_stmt (stmt); id->src_node->remove (); expand_call_inline (bb, stmt, id); + maybe_remove_unused_call_args (cfun, stmt); return true; } fn = cg_edge->callee->decl; Marek