Merge commit '279b9184c2ff4fea93b198a3519b8cb3a1d8d195'

Conflicts:
	include/llvm/CodeGen/LexicalScopes.h
	include/llvm/MC/MCAsmInfo.h
	lib/Linker/LinkArchives.cpp
	lib/Linker/LinkItems.cpp
	lib/MC/MCAsmInfo.cpp
	lib/MC/MCDwarf.cpp
	lib/Target/ARM/ARMInstrInfo.td
	lib/Target/ARM/ARMSubtarget.cpp
	lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp
	lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
	lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.cpp
	lib/Target/Mips/MipsAsmPrinter.cpp
	lib/Target/Mips/MipsDelaySlotFiller.cpp
	lib/Target/Mips/MipsISelDAGToDAG.cpp
	lib/Target/Mips/MipsSubtarget.cpp
	lib/Target/Mips/MipsSubtarget.h
	lib/Target/Mips/MipsTargetObjectFile.cpp
	lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp
	lib/Target/X86/X86FastISel.cpp
	lib/Target/X86/X86ISelLowering.cpp
	lib/Target/X86/X86TargetMachine.cpp
	lib/Transforms/CMakeLists.txt
	lib/Transforms/LLVMBuild.txt
	lib/Transforms/Makefile
	test/MC/ARM/arm_instructions.s
	test/MC/X86/AlignedBundling/pad-align-to-bundle-end.s

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 40e559eda5..bad46b4dab 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1331,6 +1331,25 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
       return new ICmpInst(TrueIfSigned ? ICmpInst::ICMP_NE : ICmpInst::ICMP_EQ,
                           And, Constant::getNullValue(And->getType()));
     }
+
+    // Transform (icmp pred iM (shl iM %v, N), CI)
+    // -> (icmp pred i(M-N) (trunc %v iM to i(N-N)), (trunc (CI>>N))
+    // Transform the shl to a trunc if (trunc (CI>>N)) has no loss.
+    // This enables to get rid of the shift in favor of a trunc which can be
+    // free on the target. It has the additional benefit of comparing to a
+    // smaller constant, which will be target friendly.
+    unsigned Amt = ShAmt->getLimitedValue(TypeBits-1);
+    if (Amt != 0 && RHSV.countTrailingZeros() >= Amt) {
+      Type *NTy = IntegerType::get(ICI.getContext(), TypeBits - Amt);
+      Constant *NCI = ConstantExpr::getTrunc(
+                        ConstantExpr::getAShr(RHS,
+                          ConstantInt::get(RHS->getType(), Amt)),
+                        NTy);
+      return new ICmpInst(ICI.getPredicate(),
+                          Builder->CreateTrunc(LHSI->getOperand(0), NTy),
+                          NCI);
+    }
+
     break;
   }