From d96514bcfe8197a8467218fa5e4b5dbaeb759eff Mon Sep 17 00:00:00 2001
From: Sanjay Patel <spatel@rotateright.com>
Date: Mon, 27 Jun 2016 17:25:57 +0000
Subject: [PATCH] [InstCombine] use m_APInt for div --> ashr fold The APInt
 matcher works with splat vectors, so we get this fold for vectors too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@273897 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../InstCombine/InstCombineMulDivRem.cpp           | 14 ++++++--------
 test/Transforms/InstCombine/exact.ll               |  9 +++++++++
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 5fb337db165..d7bd80261ab 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -1143,14 +1143,12 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) {
   if (match(Op1, m_AllOnes()))
     return BinaryOperator::CreateNeg(Op0);
 
-  if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
-    // sdiv X, C  -->  ashr exact X, log2(C)
-    if (I.isExact() && RHS->getValue().isNonNegative() &&
-        RHS->getValue().isPowerOf2()) {
-      Value *ShAmt = llvm::ConstantInt::get(RHS->getType(),
-                                            RHS->getValue().exactLogBase2());
-      return BinaryOperator::CreateExactAShr(Op0, ShAmt, I.getName());
-    }
+  // sdiv exact X, C  -->  ashr exact X, log2(C)
+  const APInt *Op1C;
+  if (match(Op1, m_APInt(Op1C)) && I.isExact() && Op1C->isNonNegative() &&
+      Op1C->isPowerOf2()) {
+    Value *ShAmt = ConstantInt::get(Op1->getType(), Op1C->exactLogBase2());
+    return BinaryOperator::CreateExactAShr(Op0, ShAmt, I.getName());
   }
 
   if (Constant *RHS = dyn_cast<Constant>(Op1)) {
diff --git a/test/Transforms/InstCombine/exact.ll b/test/Transforms/InstCombine/exact.ll
index 73b1e044a15..9edcd2491ff 100644
--- a/test/Transforms/InstCombine/exact.ll
+++ b/test/Transforms/InstCombine/exact.ll
@@ -19,6 +19,15 @@ define i32 @sdiv2(i32 %x) {
   ret i32 %y
 }
 
+define <2 x i32> @sdiv2_vec(<2 x i32> %x) {
+; CHECK-LABEL: @sdiv2_vec(
+; CHECK-NEXT:    [[Y:%.*]] = ashr exact <2 x i32> %x, <i32 7, i32 7>
+; CHECK-NEXT:    ret <2 x i32> [[Y]]
+;
+  %y = sdiv exact <2 x i32> %x, <i32 128, i32 128>
+  ret <2 x i32> %y
+}
+
 define i32 @sdiv3(i32 %x) {
 ; CHECK-LABEL: @sdiv3(
 ; CHECK-NEXT:    [[Y:%.*]] = srem i32 %x, 3