[RemoveDIs] Reapply 3fda50d3915, insert instructions using iterators

I'd reverted this in 6c7805d5d1 after a bad stage. Original commit
messsage follows:

[NFC][RemoveDIs] Bulk update utilities to insert with iterators

As part of the RemoveDIs project we need LLVM to insert instructions using
iterators wherever possible, so that the iterators can carry a bit of
debug-info. This commit implements some of that by updating the contents of
llvm/lib/Transforms/Utils to always use iterator-versions of instruction
constructors.

There are two general flavours of update:
 * Almost all call-sites just call getIterator on an instruction
 * Several make use of an existing iterator (scenarios where the code is
   actually significant for debug-info)
The underlying logic is that any call to getFirstInsertionPt or similar
APIs that identify the start of a block need to have that iterator passed
directly to the insertion function, without being converted to a bare
Instruction pointer along the way.

I've also switched DemotePHIToStack to take an optional iterator: it needs
to take an iterator, and having a no-insert-location behaviour appears to
be important. The constructors for ICmpInst and FCmpInst have been updated
too. They're the only instructions that take block _references_ rather than
pointers for certain calls, and a future patch is going to make use of
default-null block insertion locations.

All of this should be NFC.

1 files changed, 5 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/Utils/LowerSwitch.cpp b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
index 4131d36..f5921e5 100644
--- a/llvm/lib/Transforms/Utils/LowerSwitch.cpp
+++ b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
@@ -165,20 +165,20 @@ BasicBlock *NewLeafBlock(CaseRange &Leaf, Value *Val, ConstantInt *LowerBound,
   if (Leaf.Low == Leaf.High) {
     // Make the seteq instruction...
     Comp =
-        new ICmpInst(*NewLeaf, ICmpInst::ICMP_EQ, Val, Leaf.Low, "SwitchLeaf");
+        new ICmpInst(NewLeaf, ICmpInst::ICMP_EQ, Val, Leaf.Low, "SwitchLeaf");
   } else {
     // Make range comparison
     if (Leaf.Low == LowerBound) {
       // Val >= Min && Val <= Hi --> Val <= Hi
-      Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_SLE, Val, Leaf.High,
+      Comp = new ICmpInst(NewLeaf, ICmpInst::ICMP_SLE, Val, Leaf.High,
                           "SwitchLeaf");
     } else if (Leaf.High == UpperBound) {
       // Val <= Max && Val >= Lo --> Val >= Lo
-      Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_SGE, Val, Leaf.Low,
+      Comp = new ICmpInst(NewLeaf, ICmpInst::ICMP_SGE, Val, Leaf.Low,
                           "SwitchLeaf");
     } else if (Leaf.Low->isZero()) {
       // Val >= 0 && Val <= Hi --> Val <=u Hi
-      Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_ULE, Val, Leaf.High,
+      Comp = new ICmpInst(NewLeaf, ICmpInst::ICMP_ULE, Val, Leaf.High,
                           "SwitchLeaf");
     } else {
       // Emit V-Lo <=u Hi-Lo
@@ -186,7 +186,7 @@ BasicBlock *NewLeafBlock(CaseRange &Leaf, Value *Val, ConstantInt *LowerBound,
       Instruction *Add = BinaryOperator::CreateAdd(
           Val, NegLo, Val->getName() + ".off", NewLeaf);
       Constant *UpperBound = ConstantExpr::getAdd(NegLo, Leaf.High);
-      Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_ULE, Add, UpperBound,
+      Comp = new ICmpInst(NewLeaf, ICmpInst::ICMP_ULE, Add, UpperBound,
                           "SwitchLeaf");
     }
   }