This patch extends the recent and;cmp to not;test optimization to also
perform this transformation for TImode on TARGET_64BIT and DImode on -m32,
One motivation for this is that it's a step to fixing the current failure
of gcc.target/i386/pr65105-5.c on -m32.

A more direct benefit for x86_64 is that the following code:

int foo(__int128 x, __int128 y)
{
  return (x & y) == y;
}

improves (with -O2 -mbmi) from:

        movq    %rdi, %r8
        movq    %rsi, %rdi
        movq    %rdx, %rsi
        andq    %rcx, %rdi
        movq    %r8, %rax
        andq    %rdx, %rax
        movq    %rdi, %rdx
        xorq    %rsi, %rax
        xorq    %rcx, %rdx
        orq     %rdx, %rax
        sete    %al
        movzbl  %al, %eax
        ret

to the much better:

        movq    %rdi, %r8
        movq    %rsi, %rdi
        andn    %rdx, %r8, %rax
        andn    %rcx, %rdi, %rsi
        orq     %rsi, %rax
        sete    %al
        movzbl  %al, %eax
        ret

The major theme of this patch is to generalize many of i386.md's
*di3_doubleword patterns to become *<dwi>_doubleword patterns, i.e.
whenever there exists a "double word" optimization for DImode with -m32,
there should be an equivalent TImode optimization on TARGET_64BIT.

The following patch has been tested on x86_64-pc-linux-gnu with
make bootstrap and make -k check, where on TARGET_64BIT there are
no new failures, but paradoxically with --target_board=unix{-m32}
the other dg-final clause in gcc.target/i386/pr65105-5.c now fails.
Counter-intuitively, this is progress, and pr65105-5.c may now be
fixed (without using peephole2) simply by tweaking the STV pass to
handle andn/test (in a follow-up patch).
OK for mainline?


2022-06-05  Roger Sayle  <roger@nextmovesoftware.com>

gcc/ChangeLog
        * config/i386/i386.cc (ix86_rtx_costs) <COMPARE>: Provide costs
        for double word comparisons and tests (comparisons against zero).
        * config/i386/i386.md (*test<mode>_not_doubleword): Split DWI
        and;cmp into andn;cmp $0 as a pre-reload splitter.
        (define_expand and<mode>3): Generalize from SWIM1248x to SWIDWI.
        (define_insn_and_split "*anddi3_doubleword"): Rename/generalize...
        (define_insn_and_split "*and<dwi>3_doubleword"): ... to this.
        (define_insn "*andndi3_doubleword"): Rename and generalize...
        (define_insn "*andn<mode>3_doubleword): ... to this.
        (define_split): Split andn when TARGET_BMI for both <DWI> modes.
        (define_split): Split andn when !TARGET_BMI for both <DWI> modes.
        (define_expand <any_or><mode>3): Generalize from SWIM1248x to
SWIDWI.
        (define_insn_and_split "*<any_or><dwi>3_doubleword): Generalize
        from DI mode to both <DWI> modes.

gcc/testsuite/ChangeLog
        * gcc.target/i386/testnot-3.c: New test case.


Thanks again,
Roger
--