From af14bbf8c25cffb4b871f1986a189ca7628d32d2 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Fri, 9 Oct 2020 14:22:19 +0100
Subject: [PATCH] [InstCombine] foldShiftOfShiftedLogic - add support for
 nonuniform constant vectors

---
 .../InstCombine/InstCombineShifts.cpp         | 12 ++++++----
 test/Transforms/InstCombine/shift-logic.ll    | 24 +++++++++----------
 2 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/lib/Transforms/InstCombine/InstCombineShifts.cpp b/lib/Transforms/InstCombine/InstCombineShifts.cpp
index 6ead851033d..828002f44d4 100644
--- a/lib/Transforms/InstCombine/InstCombineShifts.cpp
+++ b/lib/Transforms/InstCombine/InstCombineShifts.cpp
@@ -328,8 +328,8 @@ static Instruction *foldShiftOfShiftedLogic(BinaryOperator &I,
   if (!LogicInst || !LogicInst->isBitwiseLogicOp() || !LogicInst->hasOneUse())
     return nullptr;
 
-  const APInt *C0, *C1;
-  if (!match(I.getOperand(1), m_APInt(C1)))
+  Constant *C0, *C1;
+  if (!match(I.getOperand(1), m_Constant(C1)))
     return nullptr;
 
   Instruction::BinaryOps ShiftOpcode = I.getOpcode();
@@ -341,9 +341,11 @@ static Instruction *foldShiftOfShiftedLogic(BinaryOperator &I,
   Value *X, *Y;
   auto matchFirstShift = [&](Value *V) {
     BinaryOperator *BO;
+    APInt Threshold(Ty->getScalarSizeInBits(), Ty->getScalarSizeInBits());
     return match(V, m_BinOp(BO)) && BO->getOpcode() == ShiftOpcode &&
-           match(V, m_OneUse(m_Shift(m_Value(X), m_APInt(C0)))) &&
-           (*C0 + *C1).ult(Ty->getScalarSizeInBits());
+           match(V, m_OneUse(m_Shift(m_Value(X), m_Constant(C0)))) &&
+           match(ConstantExpr::getAdd(C0, C1),
+                 m_SpecificInt_ICMP(ICmpInst::ICMP_ULT, Threshold));
   };
 
   // Logic ops are commutative, so check each operand for a match.
@@ -355,7 +357,7 @@ static Instruction *foldShiftOfShiftedLogic(BinaryOperator &I,
     return nullptr;
 
   // shift (logic (shift X, C0), Y), C1 -> logic (shift X, C0+C1), (shift Y, C1)
-  Constant *ShiftSumC = ConstantInt::get(Ty, *C0 + *C1);
+  Constant *ShiftSumC = ConstantExpr::getAdd(C0, C1);
   Value *NewShift1 = Builder.CreateBinOp(ShiftOpcode, X, ShiftSumC);
   Value *NewShift2 = Builder.CreateBinOp(ShiftOpcode, Y, I.getOperand(1));
   return BinaryOperator::Create(LogicInst->getOpcode(), NewShift1, NewShift2);
diff --git a/test/Transforms/InstCombine/shift-logic.ll b/test/Transforms/InstCombine/shift-logic.ll
index 2c79a6e8cad..437bc1688be 100644
--- a/test/Transforms/InstCombine/shift-logic.ll
+++ b/test/Transforms/InstCombine/shift-logic.ll
@@ -16,9 +16,9 @@ define i8 @shl_and(i8 %x, i8 %y) {
 
 define <2 x i8> @shl_and_nonuniform(<2 x i8> %x, <2 x i8> %y) {
 ; CHECK-LABEL: @shl_and_nonuniform(
-; CHECK-NEXT:    [[SH0:%.*]] = shl <2 x i8> [[X:%.*]], <i8 3, i8 4>
-; CHECK-NEXT:    [[R:%.*]] = and <2 x i8> [[SH0]], [[Y:%.*]]
-; CHECK-NEXT:    [[SH1:%.*]] = shl <2 x i8> [[R]], <i8 2, i8 0>
+; CHECK-NEXT:    [[TMP1:%.*]] = shl <2 x i8> [[X:%.*]], <i8 5, i8 4>
+; CHECK-NEXT:    [[TMP2:%.*]] = shl <2 x i8> [[Y:%.*]], <i8 2, i8 0>
+; CHECK-NEXT:    [[SH1:%.*]] = and <2 x i8> [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    ret <2 x i8> [[SH1]]
 ;
   %sh0 = shl <2 x i8> %x, <i8 3, i8 4>
@@ -45,9 +45,9 @@ define i16 @shl_or(i16 %x, i16 %py) {
 define <2 x i16> @shl_or_undef(<2 x i16> %x, <2 x i16> %py) {
 ; CHECK-LABEL: @shl_or_undef(
 ; CHECK-NEXT:    [[Y:%.*]] = srem <2 x i16> [[PY:%.*]], <i16 42, i16 42>
-; CHECK-NEXT:    [[SH0:%.*]] = shl <2 x i16> [[X:%.*]], <i16 5, i16 undef>
-; CHECK-NEXT:    [[R:%.*]] = or <2 x i16> [[Y]], [[SH0]]
-; CHECK-NEXT:    [[SH1:%.*]] = shl <2 x i16> [[R]], <i16 7, i16 undef>
+; CHECK-NEXT:    [[TMP1:%.*]] = shl <2 x i16> [[X:%.*]], <i16 12, i16 undef>
+; CHECK-NEXT:    [[TMP2:%.*]] = shl <2 x i16> [[Y]], <i16 7, i16 undef>
+; CHECK-NEXT:    [[SH1:%.*]] = or <2 x i16> [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    ret <2 x i16> [[SH1]]
 ;
   %y = srem <2 x i16> %py, <i16 42, i16 42> ; thwart complexity-based canonicalization
@@ -72,9 +72,9 @@ define i32 @shl_xor(i32 %x, i32 %y) {
 
 define <2 x i32> @shl_xor_nonuniform(<2 x i32> %x, <2 x i32> %y) {
 ; CHECK-LABEL: @shl_xor_nonuniform(
-; CHECK-NEXT:    [[SH0:%.*]] = shl <2 x i32> [[X:%.*]], <i32 5, i32 6>
-; CHECK-NEXT:    [[R:%.*]] = xor <2 x i32> [[SH0]], [[Y:%.*]]
-; CHECK-NEXT:    [[SH1:%.*]] = shl <2 x i32> [[R]], <i32 7, i32 8>
+; CHECK-NEXT:    [[TMP1:%.*]] = shl <2 x i32> [[X:%.*]], <i32 12, i32 14>
+; CHECK-NEXT:    [[TMP2:%.*]] = shl <2 x i32> [[Y:%.*]], <i32 7, i32 8>
+; CHECK-NEXT:    [[SH1:%.*]] = xor <2 x i32> [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    ret <2 x i32> [[SH1]]
 ;
   %sh0 = shl <2 x i32> %x, <i32 5, i32 6>
@@ -101,9 +101,9 @@ define i64 @lshr_and(i64 %x, i64 %py) {
 define <2 x i64> @lshr_and_undef(<2 x i64> %x, <2 x i64> %py) {
 ; CHECK-LABEL: @lshr_and_undef(
 ; CHECK-NEXT:    [[Y:%.*]] = srem <2 x i64> [[PY:%.*]], <i64 42, i64 42>
-; CHECK-NEXT:    [[SH0:%.*]] = lshr <2 x i64> [[X:%.*]], <i64 5, i64 undef>
-; CHECK-NEXT:    [[R:%.*]] = and <2 x i64> [[Y]], [[SH0]]
-; CHECK-NEXT:    [[SH1:%.*]] = lshr <2 x i64> [[R]], <i64 7, i64 undef>
+; CHECK-NEXT:    [[TMP1:%.*]] = lshr <2 x i64> [[X:%.*]], <i64 12, i64 undef>
+; CHECK-NEXT:    [[TMP2:%.*]] = lshr <2 x i64> [[Y]], <i64 7, i64 undef>
+; CHECK-NEXT:    [[SH1:%.*]] = and <2 x i64> [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    ret <2 x i64> [[SH1]]
 ;
   %y = srem <2 x i64> %py, <i64 42, i64 42> ; thwart complexity-based canonicalization