[llvm-branch-commits] [llvm] b7c7b42 - [ARM] Use just ARM::t2B in ARMBlockPlacementPass

[Tom Stellard via llvm-branch-commits]

Author: David Green
Date: 2021-06-25T20:20:29-07:00
New Revision: b7c7b42db1d16c4cab595bf53c62a70a6a505e0e

URL: https://github.com/llvm/llvm-project/commit/b7c7b42db1d16c4cab595bf53c62a70a6a505e0e
DIFF: https://github.com/llvm/llvm-project/commit/b7c7b42db1d16c4cab595bf53c62a70a6a505e0e.diff

LOG: [ARM] Use just ARM::t2B in ARMBlockPlacementPass

The ARMConstantIsland pass will convert any t2B to tB if they are within
range after it has added or moved any constant pools. They don't need to
be deliberately converted beforehand, and it doesn't deal with needing
to convert tB to t2B very well.

Added: 
    

Modified: 
    llvm/lib/Target/ARM/ARMBlockPlacement.cpp
    llvm/test/CodeGen/Thumb2/block-placement.mir

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/ARM/ARMBlockPlacement.cpp b/llvm/lib/Target/ARM/ARMBlockPlacement.cpp
index 581b4b9857af..9ba16003a97a 100644
--- a/llvm/lib/Target/ARM/ARMBlockPlacement.cpp
+++ b/llvm/lib/Target/ARM/ARMBlockPlacement.cpp
@@ -145,8 +145,7 @@ bool ARMBlockPlacement::runOnMachineFunction(MachineFunction &MF) {
              It++) {
           MachineBasicBlock *MBB = &*It;
           for (auto &Terminator : MBB->terminators()) {
-            if (Terminator.getOpcode() != ARM::t2LoopEnd &&
-                Terminator.getOpcode() != ARM::t2LoopEndDec)
+            if (Terminator.getOpcode() != ARM::t2LoopEndDec)
               continue;
             MachineBasicBlock *LETarget = Terminator.getOperand(2).getMBB();
             // The LE will become forwards branching if it branches to LoopExit
@@ -204,10 +203,8 @@ void ARMBlockPlacement::moveBasicBlock(MachineBasicBlock *BB,
     if (!Terminator.isUnconditionalBranch()) {
       // The BB doesn't have an unconditional branch so it relied on
       // fall-through. Fix by adding an unconditional branch to the moved BB.
-      unsigned BrOpc =
-          BBUtils->isBBInRange(&Terminator, To, 254) ? ARM::tB : ARM::t2B;
       MachineInstrBuilder MIB =
-          BuildMI(From, Terminator.getDebugLoc(), TII->get(BrOpc));
+          BuildMI(From, Terminator.getDebugLoc(), TII->get(ARM::t2B));
       MIB.addMBB(To);
       MIB.addImm(ARMCC::CondCodes::AL);
       MIB.addReg(ARM::NoRegister);

diff  --git a/llvm/test/CodeGen/Thumb2/block-placement.mir b/llvm/test/CodeGen/Thumb2/block-placement.mir
index ed4a0a6b493d..c38223baba76 100644
--- a/llvm/test/CodeGen/Thumb2/block-placement.mir
+++ b/llvm/test/CodeGen/Thumb2/block-placement.mir
@@ -48,7 +48,7 @@ body:             |
   ; CHECK: bb.2:
   ; CHECK:   successors: %bb.3(0x80000000)
   ; CHECK:   t2WhileLoopStart killed renamable $r0, %bb.1, implicit-def dead $cpsr
-  ; CHECK:   tB %bb.3, 14 /* CC::al */, $noreg
+  ; CHECK:   t2B %bb.3, 14 /* CC::al */, $noreg
   ; CHECK: bb.1:
   ; CHECK:   frame-destroy tPOP_RET 14 /* CC::al */, $noreg, def $r7, def $pc
   ; CHECK: bb.3:
@@ -145,7 +145,7 @@ body:             |
   ; CHECK:   $lr = tMOVr $r0, 14 /* CC::al */, $noreg
   ; CHECK:   renamable $r0 = t2ADDrs killed renamable $r2, killed $r0, 18, 14 /* CC::al */, $noreg, $noreg
   ; CHECK:   t2WhileLoopStart killed renamable $lr, %bb.1, implicit-def dead $cpsr
-  ; CHECK:   tB %bb.3, 14 /* CC::al */, $noreg
+  ; CHECK:   t2B %bb.3, 14 /* CC::al */, $noreg
   ; CHECK: bb.1:
   ; CHECK:   successors: %bb.4(0x80000000)
   ; CHECK:   tCMPi8 renamable $r1, 1, 14 /* CC::al */, $noreg, implicit-def $cpsr