https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108357
--- Comment #14 from Xi Ruoyao <xry111 at gcc dot gnu.org> --- (In reply to rguent...@suse.de from comment #13) > On Thu, 13 Apr 2023, chenglulu at loongson dot cn wrote: > > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108357 > > > > --- Comment #10 from chenglulu <chenglulu at loongson dot cn> --- > > (In reply to Xi Ruoyao from comment #5) > > > The test fails on loongarch64-linux-gnu. foo is kept in 114t.threadfull1, > > > but removed in 135t.forwprop3. > > > > > > Does this mean something is wrong for LoongArch, or we should simply check > > > the tree dump in a later pass (for e.g. 254t.optimized)? > > > > If the definition of the macro DEFAULT_SIGNED_CHAR is changed to 0, the test > > case can pass the test. I guess it is because the definition of > > DEFAULT_SIGNED_CHAR affects the optimization of the ccp pass, resulting in > > some > > blocks that cannot be removed, resulting in the failure of this test case. > > Can you check if making b unsigned fixes the test for you? If so > that's what we should do. It works： diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr108357.c b/gcc/testsuite/gcc.dg/tree-ssa/pr108357.c index 44c457b7a97..79cf371ef28 100644 --- a/gcc/testsuite/gcc.dg/tree-ssa/pr108357.c +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr108357.c @@ -1,7 +1,7 @@ /* { dg-do compile } */ /* { dg-options "-O2 -fdump-tree-threadfull1" } */ -static char b; +static unsigned char b; static unsigned c; void foo(); short(a)(short d, short e) { return d * e; } But I'm still wondering why this is not an issue for x86_64.
