diff options
Diffstat (limited to 'lib/CodeGen/TwoAddressInstructionPass.cpp')
| -rw-r--r-- | lib/CodeGen/TwoAddressInstructionPass.cpp | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp index 6bceccca778b..e84bea63995e 100644 --- a/lib/CodeGen/TwoAddressInstructionPass.cpp +++ b/lib/CodeGen/TwoAddressInstructionPass.cpp @@ -1207,12 +1207,24 @@ tryInstructionTransform(MachineBasicBlock::iterator &mi, } } + // If the instruction is convertible to 3 Addr, instead + // of returning try 3 Addr transformation aggresively and + // use this variable to check later. Because it might be better. + // For example, we can just use `leal (%rsi,%rdi), %eax` and `ret` + // instead of the following code. + // addl %esi, %edi + // movl %edi, %eax + // ret + bool commuted = false; + // If it's profitable to commute, try to do so. if (TryCommute && commuteInstruction(mi, regB, regC, Dist)) { + commuted = true; ++NumCommuted; if (AggressiveCommute) ++NumAggrCommuted; - return false; + if (!MI.isConvertibleTo3Addr()) + return false; } if (shouldOnlyCommute) @@ -1220,7 +1232,7 @@ tryInstructionTransform(MachineBasicBlock::iterator &mi, // If there is one more use of regB later in the same MBB, consider // re-schedule this MI below it. - if (EnableRescheduling && rescheduleMIBelowKill(mi, nmi, regB)) { + if (!commuted && EnableRescheduling && rescheduleMIBelowKill(mi, nmi, regB)) { ++NumReSchedDowns; return true; } @@ -1237,6 +1249,10 @@ tryInstructionTransform(MachineBasicBlock::iterator &mi, } } + // Return if it is commuted but 3 addr conversion is failed. + if (commuted) + return false; + // If there is one more use of regB later in the same MBB, consider // re-schedule it before this MI if it's legal. if (EnableRescheduling && rescheduleKillAboveMI(mi, nmi, regB)) { |