diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/optabs.c | 79 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/i386/pr101950-1.c | 20 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/i386/pr101950-2.c | 19 |
3 files changed, 118 insertions, 0 deletions
diff --git a/gcc/optabs.c b/gcc/optabs.c index 14d8ad2..ebed78f 100644 --- a/gcc/optabs.c +++ b/gcc/optabs.c @@ -2600,6 +2600,82 @@ widen_leading (scalar_int_mode mode, rtx op0, rtx target, optab unoptab) return 0; } +/* Attempt to emit (clrsb:mode op0) as + (plus:mode (clz:mode (xor:mode op0 (ashr:mode op0 (const_int prec-1)))) + (const_int -1)) + if CLZ_DEFINED_VALUE_AT_ZERO (mode, val) is 2 and val is prec, + or as + (clz:mode (ior:mode (xor:mode (ashl:mode op0 (const_int 1)) + (ashr:mode op0 (const_int prec-1))) + (const_int 1))) + otherwise. */ + +static rtx +expand_clrsb_using_clz (scalar_int_mode mode, rtx op0, rtx target) +{ + if (optimize_insn_for_size_p () + || optab_handler (clz_optab, mode) == CODE_FOR_nothing) + return NULL_RTX; + + start_sequence (); + HOST_WIDE_INT val = 0; + if (CLZ_DEFINED_VALUE_AT_ZERO (mode, val) != 2 + || val != GET_MODE_PRECISION (mode)) + val = 0; + else + val = 1; + + rtx temp2 = op0; + if (!val) + { + temp2 = expand_binop (mode, ashl_optab, op0, const1_rtx, + NULL_RTX, 0, OPTAB_DIRECT); + if (!temp2) + { + fail: + end_sequence (); + return NULL_RTX; + } + } + + rtx temp = expand_binop (mode, ashr_optab, op0, + GEN_INT (GET_MODE_PRECISION (mode) - 1), + NULL_RTX, 0, OPTAB_DIRECT); + if (!temp) + goto fail; + + temp = expand_binop (mode, xor_optab, temp2, temp, NULL_RTX, 0, + OPTAB_DIRECT); + if (!temp) + goto fail; + + if (!val) + { + temp = expand_binop (mode, ior_optab, temp, const1_rtx, + NULL_RTX, 0, OPTAB_DIRECT); + if (!temp) + goto fail; + } + temp = expand_unop_direct (mode, clz_optab, temp, val ? NULL_RTX : target, + true); + if (!temp) + goto fail; + if (val) + { + temp = expand_binop (mode, add_optab, temp, constm1_rtx, + target, 0, OPTAB_DIRECT); + if (!temp) + goto fail; + } + + rtx_insn *seq = get_insns (); + end_sequence (); + + add_equal_note (seq, temp, CLRSB, op0, NULL_RTX, mode); + emit_insn (seq); + return temp; +} + /* Try calculating clz of a double-word quantity as two clz's of word-sized quantities, choosing which based on whether the high word is nonzero. */ static rtx @@ -3171,6 +3247,9 @@ expand_unop (machine_mode mode, optab unoptab, rtx op0, rtx target, temp = widen_leading (int_mode, op0, target, unoptab); if (temp) return temp; + temp = expand_clrsb_using_clz (int_mode, op0, target); + if (temp) + return temp; } goto try_libcall; } diff --git a/gcc/testsuite/gcc.target/i386/pr101950-1.c b/gcc/testsuite/gcc.target/i386/pr101950-1.c new file mode 100644 index 0000000..cc98064 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr101950-1.c @@ -0,0 +1,20 @@ +/* PR middle-end/101950 */ +/* { dg-do compile } */ +/* { dg-options "-O2 -mno-lzcnt" } */ +/* { dg-final { scan-assembler-not "call\[^\n\r]*__clrsb.i2" } } */ +/* { dg-final { scan-assembler-times "\tbsr\[ql]\t" 2 } } */ +/* { dg-final { scan-assembler-times "\txor\[ql]\t" 4 } } */ +/* { dg-final { scan-assembler-times "\tor\[ql]\t" 2 } } */ +/* { dg-final { scan-assembler-times "\tsar\[ql]\t|\tcltd" 2 } } */ + +int +foo (long x) +{ + return __builtin_clrsbl (x); +} + +int +bar (int x) +{ + return __builtin_clrsb (x); +} diff --git a/gcc/testsuite/gcc.target/i386/pr101950-2.c b/gcc/testsuite/gcc.target/i386/pr101950-2.c new file mode 100644 index 0000000..896f1b4 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr101950-2.c @@ -0,0 +1,19 @@ +/* PR middle-end/101950 */ +/* { dg-do compile } */ +/* { dg-options "-O2 -mlzcnt" } */ +/* { dg-final { scan-assembler-not "call\[^\n\r]*__clrsb.i2" } } */ +/* { dg-final { scan-assembler-times "\tlzcnt\[ql]\t" 2 } } */ +/* { dg-final { scan-assembler-times "\txor\[ql]\t" 2 } } */ +/* { dg-final { scan-assembler-times "\tsar\[ql]\t|\tcltd" 2 } } */ + +int +foo (long x) +{ + return __builtin_clrsbl (x); +} + +int +bar (int x) +{ + return __builtin_clrsb (x); +} |