On Sun, Jan 15, 2023 at 11:32:27AM +0100, Aldy Hernandez wrote:
> As discussed in the PR, for trapping math, do not fold overflowing
> operations into +-INF as doing so could elide a trap.
>
> There is a minor adjustment to known_isinf() where it was mistakenly
> returning true for an [infinity U NAN], whereas it should only return
> true when the range is exclusively +INF or -INF. This is benign, as
> there were no users of known_isinf up to now.
>
> I had some testsuite issues with:
>
> > FAIL: c-c++-common/diagnostic-format-sarif-file-4.c -std=gnu++14
> > scan-sarif-file "text": " int \\\\u6587\\\\u5b57\\\\u5316\\\\u3051 =
> > FAIL: c-c++-common/diagnostic-format-sarif-file-4.c -std=gnu++17
> > scan-sarif-file "text": " int \\\\u6587\\\\u5b57\\\\u5316\\\\u3051 =
> > FAIL: c-c++-common/diagnostic-format-sarif-file-4.c -std=gnu++20
> > scan-sarif-file "text": " int \\\\u6587\\\\u5b57\\\\u5316\\\\u3051 =
> > FAIL: c-c++-common/diagnostic-format-sarif-file-4.c -std=gnu++98
> > scan-sarif-file "text": " int \\\\u6587\\\\u5b57\\\\u5316\\\\u3051 =
> > FAIL: g++.dg/pr71488.C (test for excess errors)
> > FAIL: g++.dg/guality/pr55665.C -O2 -flto -fno-use-linker-plugin
> > -flto-partition=none line 23 p == 40
> > FAIL: c-c++-common/diagnostic-format-sarif-file-4.c -Wc++-compat
> > scan-sarif-file "text": " int \\\\u6587\\\\u5b57\\\\u5316\\\\u3051 =
> < FAIL: g++.dg/pr71488.C (test for excess errors)
> < FAIL: g++.dg/guality/pr55665.C -O2 -flto -fno-use-linker-plugin
> -flto-partition=none line 23 p == 40
> > FAIL: ./index0-out.go execution, -O0 -g -fno-var-tracking-assignments
> > FAIL: go.test/test/fixedbugs/issue27836.dir/Äfoo.go -O -I. (test for
> > excess errors)
> > FAIL: go.test/test/fixedbugs/issue27836.dir/Ämain.go -O -I. (test for
> > excess errors)
>
> But they seem to be transient issues on my machine, as re-running them
> manually don't cause any issues. Also, the tests themselves have
> nothing to do with floats so I don't see how they could be related.
>
> Tested on x86-64 Linux.
>
> I also ran the glibc testsuite (git sources) on x86-64 and this patch
> fixes:
>
> -FAIL: math/test-double-lgamma
> -FAIL: math/test-double-log1p
> -FAIL: math/test-float-lgamma
> -FAIL: math/test-float-log1p
> -FAIL: math/test-float128-catan
> -FAIL: math/test-float128-catanh
> -FAIL: math/test-float128-lgamma
> -FAIL: math/test-float128-log
> -FAIL: math/test-float128-log1p
> -FAIL: math/test-float128-y0
> -FAIL: math/test-float128-y1
> -FAIL: math/test-float32-lgamma
> -FAIL: math/test-float32-log1p
> -FAIL: math/test-float32x-lgamma
> -FAIL: math/test-float32x-log1p
> -FAIL: math/test-float64-lgamma
> -FAIL: math/test-float64-log1p
> -FAIL: math/test-float64x-lgamma
> -FAIL: math/test-ldouble-lgamma
>
> OK for trunk?
>
> PR tree-optimization/107608
>
> gcc/ChangeLog:
>
> * range-op-float.cc (range_operator_float::fold_range): Avoid
> folding into INF when flag_trapping_math.
> * value-range.h (frange::known_isinf): Return false for possible NANs.
As a workaround this looks ok to me, but we need to figure out something
better for GCC 14.
Ok for trunk.
Jakub
