diff options
Diffstat (limited to 'llvm/lib/Target/ARM/ARMInstrThumb2.td')
| -rw-r--r-- | llvm/lib/Target/ARM/ARMInstrThumb2.td | 35 |
1 files changed, 29 insertions, 6 deletions
diff --git a/llvm/lib/Target/ARM/ARMInstrThumb2.td b/llvm/lib/Target/ARM/ARMInstrThumb2.td index 11413de30dc..bbe675e81ab 100644 --- a/llvm/lib/Target/ARM/ARMInstrThumb2.td +++ b/llvm/lib/Target/ARM/ARMInstrThumb2.td @@ -122,6 +122,10 @@ def imm0_255_neg : PatLeaf<(i32 imm), [{ return (uint32_t)(-N->getZExtValue()) < 255; }], imm_neg_XFORM>; +def imm0_255_not : PatLeaf<(i32 imm), [{ + return (uint32_t)(~N->getZExtValue()) < 255; +}], imm_comp_XFORM>; + // Define Thumb2 specific addressing modes. // t2addrmode_imm12 := reg + imm12 @@ -1391,13 +1395,32 @@ defm t2RSBS : T2I_rbin_s_is <0b1110, "rsb", BinOpFrag<(subc node:$LHS, node:$RHS)>>; // (sub X, imm) gets canonicalized to (add X, -imm). Match this form. +// The assume-no-carry-in form uses the negation of the input since add/sub +// assume opposite meanings of the carry flag (i.e., carry == !borrow). +// See the definition of AddWithCarry() in the ARM ARM A2.2.1 for the gory +// details. +// The AddedComplexity preferences the first variant over the others since +// it can be shrunk to a 16-bit wide encoding, while the others cannot. +let AddedComplexity = 1 in +def : T2Pat<(add GPR:$src, imm0_255_neg:$imm), + (t2SUBri GPR:$src, imm0_255_neg:$imm)>; +def : T2Pat<(add GPR:$src, t2_so_imm_neg:$imm), + (t2SUBri GPR:$src, t2_so_imm_neg:$imm)>; +def : T2Pat<(add GPR:$src, imm0_4095_neg:$imm), + (t2SUBri12 GPR:$src, imm0_4095_neg:$imm)>; +let AddedComplexity = 1 in +def : T2Pat<(addc GPR:$src, imm0_255_neg:$imm), + (t2SUBSri GPR:$src, imm0_255_neg:$imm)>; +def : T2Pat<(addc GPR:$src, t2_so_imm_neg:$imm), + (t2SUBSri GPR:$src, t2_so_imm_neg:$imm)>; +// The with-carry-in form matches bitwise not instead of the negation. +// Effectively, the inverse interpretation of the carry flag already accounts +// for part of the negation. let AddedComplexity = 1 in -def : T2Pat<(add GPR:$src, imm0_255_neg:$imm), - (t2SUBri GPR:$src, imm0_255_neg:$imm)>; -def : T2Pat<(add GPR:$src, t2_so_imm_neg:$imm), - (t2SUBri GPR:$src, t2_so_imm_neg:$imm)>; -def : T2Pat<(add GPR:$src, imm0_4095_neg:$imm), - (t2SUBri12 GPR:$src, imm0_4095_neg:$imm)>; +def : T2Pat<(adde GPR:$src, imm0_255_not:$imm), + (t2SBCSri GPR:$src, imm0_255_not:$imm)>; +def : T2Pat<(adde GPR:$src, t2_so_imm_not:$imm), + (t2SBCSri GPR:$src, t2_so_imm_not:$imm)>; // Select Bytes -- for disassembly only |
