1 files changed, 97 insertions, 26 deletions

diff --git a/llvm/lib/Target/ARM/ARMFrameLowering.cpp b/llvm/lib/Target/ARM/ARMFrameLowering.cpp
index 1f2f6f7497e0..b9b417865691 100644
--- a/llvm/lib/Target/ARM/ARMFrameLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMFrameLowering.cpp
@@ -2488,6 +2488,7 @@ void ARMFrameLowering::adjustForSegmentedStacks(
   unsigned CFIIndex;
   const ARMSubtarget *ST = &MF.getSubtarget<ARMSubtarget>();
   bool Thumb = ST->isThumb();
+  bool Thumb2 = ST->isThumb2();
 
   // Sadly, this currently doesn't support varargs, platforms other than
   // android/linux. Note that thumb1/thumb2 are support for android/linux.
@@ -2630,17 +2631,46 @@ void ARMFrameLowering::adjustForSegmentedStacks(
 
   // sub SR1, sp, #StackSize
   if (!CompareStackPointer && Thumb) {
-    BuildMI(McrMBB, DL, TII.get(ARM::tSUBi8), ScratchReg1)
-        .add(condCodeOp())
-        .addReg(ScratchReg1)
-        .addImm(AlignedStackSize)
-        .add(predOps(ARMCC::AL));
+    if (AlignedStackSize < 256) {
+      BuildMI(McrMBB, DL, TII.get(ARM::tSUBi8), ScratchReg1)
+          .add(condCodeOp())
+          .addReg(ScratchReg1)
+          .addImm(AlignedStackSize)
+          .add(predOps(ARMCC::AL));
+    } else {
+      if (Thumb2) {
+        BuildMI(McrMBB, DL, TII.get(ARM::t2MOVi32imm), ScratchReg0)
+            .addImm(AlignedStackSize);
+      } else {
+        auto MBBI = McrMBB->end();
+        auto RegInfo = STI.getRegisterInfo();
+        RegInfo->emitLoadConstPool(*McrMBB, MBBI, DL, ScratchReg0, 0,
+                                   AlignedStackSize);
+      }
+      BuildMI(McrMBB, DL, TII.get(ARM::tSUBrr), ScratchReg1)
+          .add(condCodeOp())
+          .addReg(ScratchReg1)
+          .addReg(ScratchReg0)
+          .add(predOps(ARMCC::AL));
+    }
   } else if (!CompareStackPointer) {
-    BuildMI(McrMBB, DL, TII.get(ARM::SUBri), ScratchReg1)
-        .addReg(ARM::SP)
-        .addImm(AlignedStackSize)
-        .add(predOps(ARMCC::AL))
-        .add(condCodeOp());
+    if (AlignedStackSize < 256) {
+      BuildMI(McrMBB, DL, TII.get(ARM::SUBri), ScratchReg1)
+          .addReg(ARM::SP)
+          .addImm(AlignedStackSize)
+          .add(predOps(ARMCC::AL))
+          .add(condCodeOp());
+    } else {
+      auto MBBI = McrMBB->end();
+      auto RegInfo = STI.getRegisterInfo();
+      RegInfo->emitLoadConstPool(*McrMBB, MBBI, DL, ScratchReg0, 0,
+                                 AlignedStackSize);
+      BuildMI(McrMBB, DL, TII.get(ARM::SUBrr), ScratchReg1)
+          .addReg(ARM::SP)
+          .addReg(ScratchReg0)
+          .add(predOps(ARMCC::AL))
+          .add(condCodeOp());
+    }
   }
 
   if (Thumb && ST->isThumb1Only()) {
@@ -2707,28 +2737,69 @@ void ARMFrameLowering::adjustForSegmentedStacks(
   // Pass first argument for the __morestack by Scratch Register #0.
   //   The amount size of stack required
   if (Thumb) {
-    BuildMI(AllocMBB, DL, TII.get(ARM::tMOVi8), ScratchReg0)
-        .add(condCodeOp())
-        .addImm(AlignedStackSize)
-        .add(predOps(ARMCC::AL));
+    if (AlignedStackSize < 256) {
+      BuildMI(AllocMBB, DL, TII.get(ARM::tMOVi8), ScratchReg0)
+          .add(condCodeOp())
+          .addImm(AlignedStackSize)
+          .add(predOps(ARMCC::AL));
+    } else {
+      if (Thumb2) {
+        BuildMI(AllocMBB, DL, TII.get(ARM::t2MOVi32imm), ScratchReg0)
+            .addImm(AlignedStackSize);
+      } else {
+        auto MBBI = AllocMBB->end();
+        auto RegInfo = STI.getRegisterInfo();
+        RegInfo->emitLoadConstPool(*AllocMBB, MBBI, DL, ScratchReg0, 0,
+                                   AlignedStackSize);
+      }
+    }
   } else {
-    BuildMI(AllocMBB, DL, TII.get(ARM::MOVi), ScratchReg0)
-        .addImm(AlignedStackSize)
-        .add(predOps(ARMCC::AL))
-        .add(condCodeOp());
+    if (AlignedStackSize < 256) {
+      BuildMI(AllocMBB, DL, TII.get(ARM::MOVi), ScratchReg0)
+          .addImm(AlignedStackSize)
+          .add(predOps(ARMCC::AL))
+          .add(condCodeOp());
+    } else {
+      auto MBBI = AllocMBB->end();
+      auto RegInfo = STI.getRegisterInfo();
+      RegInfo->emitLoadConstPool(*AllocMBB, MBBI, DL, ScratchReg0, 0,
+                                 AlignedStackSize);
+    }
   }
+
   // Pass second argument for the __morestack by Scratch Register #1.
   //   The amount size of stack consumed to save function arguments.
   if (Thumb) {
-    BuildMI(AllocMBB, DL, TII.get(ARM::tMOVi8), ScratchReg1)
-        .add(condCodeOp())
-        .addImm(alignToARMConstant(ARMFI->getArgumentStackSize()))
-        .add(predOps(ARMCC::AL));
+    if (ARMFI->getArgumentStackSize() < 256) {
+      BuildMI(AllocMBB, DL, TII.get(ARM::tMOVi8), ScratchReg1)
+          .add(condCodeOp())
+          .addImm(alignToARMConstant(ARMFI->getArgumentStackSize()))
+          .add(predOps(ARMCC::AL));
+    } else {
+      if (Thumb2) {
+        BuildMI(AllocMBB, DL, TII.get(ARM::t2MOVi32imm), ScratchReg1)
+            .addImm(alignToARMConstant(ARMFI->getArgumentStackSize()));
+      } else {
+        auto MBBI = AllocMBB->end();
+        auto RegInfo = STI.getRegisterInfo();
+        RegInfo->emitLoadConstPool(
+            *AllocMBB, MBBI, DL, ScratchReg1, 0,
+            alignToARMConstant(ARMFI->getArgumentStackSize()));
+      }
+    }
   } else {
-    BuildMI(AllocMBB, DL, TII.get(ARM::MOVi), ScratchReg1)
-        .addImm(alignToARMConstant(ARMFI->getArgumentStackSize()))
-        .add(predOps(ARMCC::AL))
-        .add(condCodeOp());
+    if (alignToARMConstant(ARMFI->getArgumentStackSize()) < 256) {
+      BuildMI(AllocMBB, DL, TII.get(ARM::MOVi), ScratchReg1)
+          .addImm(alignToARMConstant(ARMFI->getArgumentStackSize()))
+          .add(predOps(ARMCC::AL))
+          .add(condCodeOp());
+    } else {
+      auto MBBI = AllocMBB->end();
+      auto RegInfo = STI.getRegisterInfo();
+      RegInfo->emitLoadConstPool(
+          *AllocMBB, MBBI, DL, ScratchReg1, 0,
+          alignToARMConstant(ARMFI->getArgumentStackSize()));
+    }
   }
 
   // push {lr} - Save return address of this function.