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| author | Richard Stallman <rms@gnu.org> | 1993-07-13 07:34:25 +0000 |
|---|---|---|
| committer | Richard Stallman <rms@gnu.org> | 1993-07-13 07:34:25 +0000 |
| commit | 7a87bc57141f13a09196ae48a4cabc120f5f45b6 (patch) | |
| tree | 5c8c31f61d9e4689ede8625d6bb712d3446952c6 | |
| parent | da3c61151d5e85eb4723f3e8f5a2ed1c33e56ea6 (diff) | |
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(ffssi2, ffshi2): Assume bsf produces garbage if input is 0.
(ffssi2, ffshi2): Assume bsf produces
garbage if input is 0. Use jumps to load output in that case.
From-SVN: r4911
| -rw-r--r-- | gcc/config/i386/i386.md | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md index 3b91864..983f497 100644 --- a/gcc/config/i386/i386.md +++ b/gcc/config/i386/i386.md @@ -4460,12 +4460,17 @@ "" "* { - rtx xops[2]; + rtx xops[3]; xops[0] = operands[0]; - xops[1] = constm1_rtx; - output_asm_insn (AS2 (mov%L0,%1,%0), xops); - return AS2 (bsf%L0,%1,%0); + xops[1] = operands[1]; + xops[2] = constm1_rtx; + /* Can there be a way to avoid the jump here? */ + output_asm_insn (AS2 (bsf%L0,%1,%0), xops); + output_asm_insn (\"jnz 1f\", xops); + output_asm_insn (AS2 (mov%L0,%2,%0), xops); + output_asm_insn (\"1:\", xops); + return \"\"; }") (define_expand "ffshi2" @@ -4484,12 +4489,16 @@ "" "* { - rtx xops[2]; + rtx xops[3]; xops[0] = operands[0]; - xops[1] = constm1_rtx; - output_asm_insn (AS2 (mov%W0,%1,%0), xops); - return AS2 (bsf%W0,%1,%0); + xops[1] = operands[1]; + xops[2] = constm1_rtx; + output_asm_insn (AS2 (bsf%W0,%1,%0), xops); + output_asm_insn (\"jnz 1f\", xops); + output_asm_insn (AS2 (mov%W0,%2,%0), xops); + output_asm_insn (\"1:\", xops); + return \"\"; }") ;; These patterns match the binary 387 instructions for addM3, subM3, |