diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp | 47 | ||||
| -rw-r--r-- | llvm/lib/Target/PowerPC/README.txt | 11 |
2 files changed, 29 insertions, 29 deletions
diff --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp index 2e1c1abf5b6..868659421c7 100644 --- a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp +++ b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp @@ -602,16 +602,19 @@ static unsigned SelectInt64CountDirect(int64_t Imm) { return Result; } +static uint64_t Rot64(uint64_t Imm, unsigned R) { + return (Imm << R) | (Imm >> (64 - R)); +} + static unsigned SelectInt64Count(int64_t Imm) { - unsigned DirectCount = SelectInt64CountDirect(Imm); + unsigned Count = SelectInt64CountDirect(Imm); - // If might be cheaper to materialize the bit-inverted constant, and then - // flip the bits (which takes one nor instruction). - unsigned NotDirectCount = SelectInt64CountDirect(~(uint64_t) Imm) + 1; - if (NotDirectCount < DirectCount) - return NotDirectCount; + for (unsigned r = 1; r < 63; ++r) { + unsigned RCount = SelectInt64CountDirect(Rot64(Imm, r)) + 1; + Count = std::min(Count, RCount); + } - return DirectCount; + return Count; } // Select a 64-bit constant. For cost-modeling purposes, SelectInt64Count @@ -691,19 +694,27 @@ static SDNode *SelectInt64Direct(SelectionDAG *CurDAG, SDLoc dl, int64_t Imm) { } static SDNode *SelectInt64(SelectionDAG *CurDAG, SDLoc dl, int64_t Imm) { - unsigned DirectCount = SelectInt64CountDirect(Imm); - - // If might be cheaper to materialize the bit-inverted constant, and then - // flip the bits (which takes one nor instruction). - unsigned NotDirectCount = SelectInt64CountDirect(~(uint64_t) Imm) + 1; - if (NotDirectCount < DirectCount) { - SDValue NotDirectVal = - SDValue(SelectInt64Direct(CurDAG, dl, ~(uint64_t) Imm), 0); - return CurDAG->getMachineNode(PPC::NOR8, dl, MVT::i64, NotDirectVal, - NotDirectVal); + unsigned Count = SelectInt64CountDirect(Imm); + unsigned RMin = 0; + + for (unsigned r = 1; r < 63; ++r) { + unsigned RCount = SelectInt64CountDirect(Rot64(Imm, r)) + 1; + if (RCount < Count) { + Count = RCount; + RMin = r; + } } - return SelectInt64Direct(CurDAG, dl, Imm); + if (!RMin) + return SelectInt64Direct(CurDAG, dl, Imm); + + auto getI32Imm = [CurDAG](unsigned Imm) { + return CurDAG->getTargetConstant(Imm, MVT::i32); + }; + + SDValue Val = SDValue(SelectInt64Direct(CurDAG, dl, Rot64(Imm, RMin)), 0); + return CurDAG->getMachineNode(PPC::RLDICL, dl, MVT::i64, Val, + getI32Imm(64 - RMin), getI32Imm(0)); } // Select a 64-bit constant. diff --git a/llvm/lib/Target/PowerPC/README.txt b/llvm/lib/Target/PowerPC/README.txt index 22162fb0de7..c5491abdbd2 100644 --- a/llvm/lib/Target/PowerPC/README.txt +++ b/llvm/lib/Target/PowerPC/README.txt @@ -8,7 +8,6 @@ TODO: On PPC64, this: long f2 (long x) { return 0xfffffff000000000UL; } -long f3 (long x) { return 0x1ffffffffUL; } could compile into: @@ -16,10 +15,6 @@ _f2: li r3,-1 rldicr r3,r3,0,27 blr -_f3: - li r3,-1 - rldicl r3,r3,0,31 - blr we produce: @@ -28,12 +23,6 @@ _f2: ori r2, r2, 65535 sldi r3, r2, 36 blr -_f3: - li r2, 1 - sldi r2, r2, 32 - oris r2, r2, 65535 - ori r3, r2, 65535 - blr ===-------------------------------------------------------------------------=== |
