Re: [PR66726] Fix regression caused by Factor conversion out of COND_EXPR

[Jeff Law <law@redhat.com>]

On 06/01/2016 04:46 AM, kugan wrote:
>
> Hi All,
>
> Factoring out CONVERT_EXPR introduced a regression for (PR66726). I had
> to revert my previous patch due to some regressions. This is a much
> simplified version compared to the one I reverted.
>
> There is a test-case (pr46309.c) in the test-suite which is valid for
> targets that has branch cost greater than 1.
>
> This patch makes optimize_range_tests understand the factored out
> COND_EXPR. i.e., Updated the final_range_test_p to look for the new
> pattern. Changed the maybe_optimize_range_tests (which does the inter
> basic block range test optimization) accordingly.
>
> With the patch
> m68k-linux-gnu-gcc -O2 -S pr46309.c -fdump-tree-reassoc-details
> grep -e "Optimizing range tests" -e into
> pr46309.c.*.reassoc1pr46309.c.114t.reassoc1:Optimizing range tests
> a_6(D) -[1, 1] and -[2, 2] and -[3, 3] and -[4, 4]
> pr46309.c.114t.reassoc1: into (unsigned int) a_6(D) + 4294967295 > 3
> pr46309.c.114t.reassoc1: into _10 = _13;
> pr46309.c.114t.reassoc1:Optimizing range tests a_6(D) -[1, 1] and -[2,
> 2] and -[3, 3] and -[4, 4]
> pr46309.c.114t.reassoc1: into (unsigned int) a_6(D) + 4294967295 > 3
> pr46309.c.114t.reassoc1: into _10 = _13;
> pr46309.c.114t.reassoc1:Optimizing range tests a_4(D) -[1, 1] and -[3, 3]
> pr46309.c.114t.reassoc1: into (a_4(D) & -3) != 1
> pr46309.c.114t.reassoc1: into _6 = _8;
> pr46309.c.114t.reassoc1:Optimizing range tests a_4(D) -[1, 1] and -[2, 2]
> pr46309.c.114t.reassoc1: into (unsigned int) a_4(D) + 4294967295 > 1
> pr46309.c.114t.reassoc1: into _6 = _9;
> pr46309.c.114t.reassoc1:Optimizing range tests a_5(D) -[0, 31] and -[64,
> 95]
> pr46309.c.114t.reassoc1: into (a_5(D) & 4294967231) > 31
> pr46309.c.114t.reassoc1: into _7 = _9;
> pr46309.c.114t.reassoc1:Optimizing range tests a_9(D) -[0, 31] and -[64,
> 95]
> pr46309.c.114t.reassoc1: into (a_9(D) & 4294967231) > 31
> pr46309.c.114t.reassoc1:Optimizing range tests a_9(D) -[128, 159] and
> -[192, 223]
> pr46309.c.114t.reassoc1: into (a_9(D) & 4294967231) + 4294967168 > 31
> pr46309.c.114t.reassoc1: into _13 = _18 | _15;
> pr46309.c.116t.reassoc1:Optimizing range tests a_2(D) -[1, 1] and -[2,
> 2] and -[3, 3] and -[4, 4]
> pr46309.c.116t.reassoc1: into (unsigned int) a_2(D) + 4294967295 > 3
> pr46309.c.116t.reassoc1:Optimizing range tests a_2(D) -[1, 1] and -[2,
> 2] and -[3, 3] and -[4, 4]
> pr46309.c.116t.reassoc1: into (unsigned int) a_2(D) + 4294967295 > 3
> pr46309.c.116t.reassoc1:Optimizing range tests a_3(D) -[0, 31] and -[64,
> 95]
> pr46309.c.116t.reassoc1: into (a_3(D) & 4294967231) > 31
> pr46309.c.116t.reassoc1:Optimizing range tests a_5(D) -[0, 31] and -[64,
> 95]
> pr46309.c.116t.reassoc1: into (a_5(D) & 4294967231) > 31
> pr46309.c.116t.reassoc1:Optimizing range tests a_5(D) -[128, 159] and
> -[192, 223]
> pr46309.c.116t.reassoc1: into (a_5(D) & 4294967231) + 4294967168 > 31
>
>
> Bootstrapped and regression testing on x86-64-linux-gnu and
> ppc64le-linux-gnu doesn't have any new regressions. Also did regression
> testing arm variants which has branch cost greater than 1
>
> Is this OK for trunk.
>
> Thanks,
> Kugan
>
> gcc/ChangeLog:
>
> 2016-06-01  Kugan Vivekanandarajah  <kuganv@linaro.org>
>
>     PR middle-end/66726
>     * tree-ssa-reassoc.c (optimize_vec_cond_expr): Handle tcc_compare stmt
>     whose result is used in PHI
>     (final_range_test_p): Likewise.
>     (maybe_optimize_range_tests): Likewise.
OK for the trunk.

Thanks for your patience,
Jeff