diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/Hexagon/HexagonConstExtenders.cpp | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/llvm/lib/Target/Hexagon/HexagonConstExtenders.cpp b/llvm/lib/Target/Hexagon/HexagonConstExtenders.cpp index 294a6da69f5..cb23f9b4815 100644 --- a/llvm/lib/Target/Hexagon/HexagonConstExtenders.cpp +++ b/llvm/lib/Target/Hexagon/HexagonConstExtenders.cpp @@ -999,15 +999,19 @@ unsigned HCE::getDirectRegReplacement(unsigned ExtOpc) const { return 0; } -// Return the allowable deviation from the current value of Rb which the +// Return the allowable deviation from the current value of Rb (i.e. the +// range of values that can be added to the current value) which the // instruction MI can accommodate. // The instruction MI is a user of register Rb, which is defined via an // extender. It may be possible for MI to be tweaked to work for a register // defined with a slightly different value. For example -// ... = L2_loadrub_io Rb, 0 +// ... = L2_loadrub_io Rb, 1 // can be modifed to be -// ... = L2_loadrub_io Rb', 1 -// if Rb' = Rb-1. +// ... = L2_loadrub_io Rb', 0 +// if Rb' = Rb+1. +// The range for Rb would be [Min+1, Max+1], where [Min, Max] is a range +// for L2_loadrub with offset 0. That means that Rb could be replaced with +// Rc, where Rc-Rb belongs to [Min+1, Max+1]. OffsetRange HCE::getOffsetRange(Register Rb, const MachineInstr &MI) const { unsigned Opc = MI.getOpcode(); // Instructions that are constant-extended may be replaced with something @@ -1618,7 +1622,7 @@ bool HCE::replaceInstrExpr(const ExtDesc &ED, const ExtenderInit &ExtI, assert(IdxOpc == Hexagon::A2_addi); // Clamp Diff to the 16 bit range. - int32_t D = isInt<16>(Diff) ? Diff : (Diff > 32767 ? 32767 : -32767); + int32_t D = isInt<16>(Diff) ? Diff : (Diff > 0 ? 32767 : -32768); BuildMI(MBB, At, dl, HII->get(IdxOpc)) .add(MI.getOperand(0)) .add(MachineOperand(ExtR)) @@ -1626,11 +1630,13 @@ bool HCE::replaceInstrExpr(const ExtDesc &ED, const ExtenderInit &ExtI, Diff -= D; #ifndef NDEBUG // Make sure the output is within allowable range for uses. + // "Diff" is a difference in the "opposite direction", i.e. Ext - DefV, + // not DefV - Ext, as the getOffsetRange would calculate. OffsetRange Uses = getOffsetRange(MI.getOperand(0)); - if (!Uses.contains(Diff)) - dbgs() << "Diff: " << Diff << " out of range " << Uses + if (!Uses.contains(-Diff)) + dbgs() << "Diff: " << -Diff << " out of range " << Uses << " for " << MI; - assert(Uses.contains(Diff)); + assert(Uses.contains(-Diff)); #endif MBB.erase(MI); return true; |
