PR middle-end/31723
    * hooks.c (hook_tree_tree_bool_null): New hook.
    * hooks.h (hook_tree_tree_bool_null): Add prototype.
    * tree-pass.h (pass_convert_to_rsqrt): Declare.
    * passes.c (init_optimization_passes): Add pass_convert_to_rsqrt.
    * tree-ssa-math-opts.c (execute_cse_reciprocals): Scan for a/func(b)
    and convert it to reciprocal a*rfunc(b).
    (execute_convert_to_rsqrt): New function.
    (gate_convert_to_rsqrt): New function.
    (pass_convert_to_rsqrt): New pass definition.
    * target.h (struct gcc_target): Add builtin_reciprocal.
    * target-def.h (TARGET_BUILTIN_RECIPROCAL): New define.
    (TARGET_INITIALIZER): Initialize builtin_reciprocal with
    TARGET_BUILTIN_RECIPROCAL.
    * doc/tm.texi (TARGET_BUILTIN_RECIPROCAL): Document.

    * config/i386/i386.h (TARGET_RECIP): New define.
    * config/i386/i386.md (divsf3): Expand by calling ix86_emit_swdivsf
    for TARGET_SSE_MATH and TARGET_RECIP when
    flag_unsafe_math_optimizations is set and not optimizing for size.
    (*rcpsf2_sse): New insn pattern.
    (*rsqrtsf2_sse): Ditto.
    (rsqrtsf2): New expander.  Expand by calling ix86_emit_swsqrtsf
    for TARGET_SSE_MATH and TARGET_RECIP when
    flag_unsafe_math_optimizations is set and not optimizing for size.
    (sqrt<mode>2): Expand SFmode operands by calling ix86_emit_swsqrtsf
    for TARGET_SSE_MATH and TARGET_RECIP when
    flag_unsafe_math_optimizations is set and not optimizing for size.
    * config/i386/sse.md (divv4sf): Expand by calling ix86_emit_swdivsf
    for TARGET_SSE_MATH and TARGET_RECIP when
    flag_unsafe_math_optimizations is set and not optimizing for size.
    (*sse_rsqrtv4sf2): Do not export.
    (sqrtv4sf2): Ditto.
    (sse_rsqrtv4sf2): New expander.  Expand by calling ix86_emit_swsqrtsf
    for TARGET_SSE_MATH and TARGET_RECIP when
    flag_unsafe_math_optimizations is set and not optimizing for size.
    (sqrtv4sf2): Ditto.
    * config/i386/i386.opt (mrecip): New option.
    * config/i386/i386-protos.h (ix86_emit_swdivsf): Declare.
    (ix86_emit_swsqrtsf): Ditto.
    * config/i386/i386.c (IX86_BUILTIN_RSQRTF): New constant.
    (ix86_init_mmx_sse_builtins): __builtin_ia32_rsqrtf: New
    builtin definition.
    (ix86_expand_builtin): Expand IX86_BUILTIN_RSQRTF using
    ix86_expand_unop1_builtin.
    (ix86_emit_swdivsf): New function.
    (ix86_emit_swsqrtsf): Ditto.
    (ix86_builtin_reciprocal): New function.
    (TARGET_BUILTIN_RECIPROCAL): Use it.
    (ix86_vectorize_builtin_conversion): Rename from
    ix86_builtin_conversion.
    (TARGET_VECTORIZE_BUILTIN_CONVERSION): Use renamed function.
    * doc/invoke.texi (Machine Dependent Options): Add -mrecip to
    "i386 and x86_64 Options" section.
    (Intel 386 and AMD x86_64 Options): Document -mrecip.

testsuite/ChangeLog:

    PR middle-end/31723
    * gcc.target/i386/recip-divf.c: New test.
    * gcc.target/i386/recip-sqrtf.c: Ditto.
    * gcc.target/i386/recip-vec-divf.c: Ditto.
    * gcc.target/i386/recip-vec-sqrtf.c: Ditto.
    * gcc.target/i386/sse-recip.c: Ditto.

From-SVN: r125756