On Sun, May 7, 2017 at 8:06 AM, Jeff Law <l...@redhat.com> wrote: > On 05/06/2017 05:56 PM, Andrew Pinski wrote: >> >> On Sat, May 6, 2017 at 4:55 PM, Andrew Pinski <pins...@gmail.com> wrote: >>> >>> On Sat, May 6, 2017 at 8:03 AM, Jeff Law <l...@redhat.com> wrote: >>>> >>>> This is the 2nd of 3-5 patches to address pr78496. >>>> >>>> Jump threading will examine ASSERT_EXPRs as it walks the IL and record >>>> information from those ASSERT_EXPRs into the available expression and >>>> const/copies tables where they're later used to simplify conditionals. >>>> >>>> We're missing a couple things though. >>>> >>>> First an ASSERT_EXPR with an EQ test creates an equality we can enter >>>> into >>>> the const/copy tables. We were failing to do that. This is most >>>> interesting when the RHS of the condition in the ASSERT_EXPR is a >>>> constant, >>>> obviously. This has a secondary benefit of doing less work to get >>>> better >>>> optimization. >>>> >>>> Second, some ASSERT_EXPRs may start off as a relational test such as x >>>> <= 0, >>>> but after range extraction and propagation they could be simplified into >>>> an >>>> equality comparison. We already do this with conditionals and >>>> generalizing >>>> that code to handle ASSERT_EXPRs is pretty easy. This gives us more >>>> chances >>>> to extract simple equivalences from the condition in ASSERT_EXPRs. >>>> >>>> This patch fixes those 2 problems. I don't think it directly helps >>>> pr78496 >>>> right now as we're unable to pick up the newly exposed jump threads >>>> until >>>> VRP2. But that's a short term limitation that I've already addressed >>>> locally :-) >>>> >>>> Bootstrapped, regression tested and installed on the trunk. >>> >>> >>> >>> After this patch on aarch64-linux-gnu I get a bootstrap failure while >>> linking lto1/cc1/cc1plus/go1 in stage2: >>> godump.o: In function `go_define(unsigned int, char const*)': >>> godump.c:(.text+0x36c): relocation truncated to fit: >>> R_AARCH64_ADR_PREL_LO21 against `.rodata' >>> godump.c:(.text+0x4b4): relocation truncated to fit: >>> R_AARCH64_ADR_PREL_LO21 against `.rodata' >>> collect2: error: ld returned 1 exit status >>> ../../gcc/gcc/lto/Make-lang.in:81: recipe for target 'lto1' failed >>> make[3]: *** [lto1] Error 1 >> >> >> I should mention this is even after the patch to >> simplify_assert_expr_using_ranges . > > Just spun up an aarch64 machine for testing and it's failing for me too. > I'll revert the patch and dig in.
Looks like I misread my regression hunter output. This patch was not the cause. I will write to the person who actually caused it. Thanks, Andrew > > jeff
