diff options
| author | Jan Hubicka <hubicka@freesoft.cz> | 1999-10-02 19:54:05 +0200 |
|---|---|---|
| committer | Richard Henderson <rth@gcc.gnu.org> | 1999-10-02 10:54:05 -0700 |
| commit | e0dc26ffad1bf2844875ed011a0aceefdcd47988 (patch) | |
| tree | 1beb140f94551a08da7b3f146168fdec78290d34 /gcc | |
| parent | fc78679f9ea238ac416e76b145a5afaabd16f77c (diff) | |
| download | gcc-e0dc26ffad1bf2844875ed011a0aceefdcd47988.zip gcc-e0dc26ffad1bf2844875ed011a0aceefdcd47988.tar.gz gcc-e0dc26ffad1bf2844875ed011a0aceefdcd47988.tar.bz2 | |
Jan Hubicka <hubicka@freesoft.cz>
* i386.md (ffs expander): Emit Pentium friendly code for
TARGET_PENTIUM.
From-SVN: r29769
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/config/i386/i386.md | 56 |
2 files changed, 58 insertions, 3 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 62642b4..985c4c9 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +Sat Oct 2 10:53:22 1999 Jan Hubicka <hubicka@freesoft.cz> + + * i386.md (ffs expander): Emit Pentium friendly code for + TARGET_PENTIUM. + Sat Oct 2 02:48:21 1999 Mark P. Mitchell <mark@codesourcery.com> * tree.c (build): Don't look at TREE_SIDE_EFFECTS or TREE_RAISES diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md index b2adc39..a8281cc 100644 --- a/gcc/config/i386/i386.md +++ b/gcc/config/i386/i386.md @@ -6779,6 +6779,57 @@ const0_rtx), tmp, out))); + emit_insn (gen_addsi3 (out, out, const1_rtx)); + emit_move_insn (operands[0], out); + } + + /* Pentium bsf instruction is extremly slow. Following code is recommended by + the Intel Optimizing Manual as resonable replacement: + TEST EAX,EAX + JZ SHORT BS2 + XOR ECX,ECX + MOV DWORD PTR [TEMP+4],ECX + SUB ECX,EAX + AND EAX,ECX + MOV DWORD PTR [TEMP],EAX + FILD QWORD PTR [TEMP] + FSTP QWORD PTR [TEMP] + WAIT ; WAIT only needed for compatibility with + ; earlier processors + MOV ECX, DWORD PTR [TEMP+4] + SHR ECX,20 + SUB ECX,3FFH + TEST EAX,EAX ; clear zero flag + BS2: + Following piece of code expand ffs to similar beast. + */ + + else if (TARGET_PENTIUM && !optimize_size && TARGET_80387) + { + rtx label = gen_label_rtx (); + rtx lo, hi; + rtx mem = assign_386_stack_local (DImode, 0); + rtx fptmp = gen_reg_rtx (DFmode); + split_di (&mem, 1, &lo, &hi); + + emit_move_insn (out, const0_rtx); + + emit_cmp_and_jump_insns (in, const0_rtx, EQ, 0, SImode, 1, 0, label); + + emit_move_insn (hi, out); + emit_insn (gen_subsi3 (out, out, in)); + emit_insn (gen_andsi3 (out, out, in)); + emit_move_insn (lo, out); + emit_insn (gen_floatdidf2 (fptmp,mem)); + emit_move_insn (gen_rtx_MEM (DFmode, XEXP (mem, 0)), fptmp); + emit_move_insn (out, hi); + emit_insn (gen_lshrsi3 (out, out, GEN_INT (20))); + emit_insn (gen_subsi3 (out, out, GEN_INT (0x3fe))); + + emit_label (label); + LABEL_NUSES (label) = 1; + + emit_move_insn (operands[0], out); } else { @@ -6790,10 +6841,9 @@ const0_rtx))); emit_insn (gen_negsi2 (tmp, tmp)); emit_insn (gen_iorsi3 (out, out, tmp)); + emit_insn (gen_addsi3 (out, out, const1_rtx)); + emit_move_insn (operands[0], out); } - emit_insn (gen_addsi3 (out, out, const1_rtx)); - - emit_move_insn (operands[0], out); DONE; }") |