[ARM] f16 constant pool fix

This is a follow up of r325012, that allowed half types in constant pools.
Proper alignment was enforced when a big basic block was split up, but not when
a CPE was placed before/after a block; the successor block had the wrong
alignment.

Differential Revision: https://reviews.llvm.org/D43580

llvm-svn: 325754

1 files changed, 2 insertions, 4 deletions

diff --git a/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp b/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
index 32c88bca186..46e804ded28 100644
--- a/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -1425,10 +1425,6 @@ void ARMConstantIslands::createNewWater(unsigned CPUserIndex,
         assert(!isThumb || getITInstrPredicate(*MI, PredReg) == ARMCC::AL));
 
   NewMBB = splitBlockBeforeInstr(&*MI);
-
-  // 4 byte align the next block after the constant pool when the CPE is a
-  // 16-bit value in ARM mode, and 2 byte for Thumb.
-  NewMBB->setAlignment(isThumb ? 1 : 2);
 }
 
 /// handleConstantPoolUser - Analyze the specified user, checking to see if it
@@ -1489,6 +1485,8 @@ bool ARMConstantIslands::handleConstantPoolUser(unsigned CPUserIndex,
     // We are adding new water.  Update NewWaterList.
     NewWaterList.insert(NewIsland);
   }
+  // Always align the new block because CP entries can be smaller than 4 bytes.
+  NewMBB->setAlignment(isThumb ? 1 : 2);
 
   // Remove the original WaterList entry; we want subsequent insertions in
   // this vicinity to go after the one we're about to insert.  This