[LoopPred] Hoist and of predicated checks where legal
If we have multiple range checks which can be predicated, hoist the and of the results outside the loop. This minorly cleans up the resulting IR, but the main motivation is as a building block for D60093.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358419 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopPredication.cpp b/lib/Transforms/Scalar/LoopPredication.cpp
index 8487278..3b27364 100644
--- a/lib/Transforms/Scalar/LoopPredication.cpp
+++ b/lib/Transforms/Scalar/LoopPredication.cpp
@@ -264,6 +264,12 @@
Optional<LoopICmp> parseLoopLatchICmp();
+ /// Return an insertion point suitable for inserting a safe to speculate
+ /// instruction whose only user will be 'User' which has operands 'Ops'. A
+ /// trivial result would be the at the User itself, but we try to return a
+ /// loop invariant location if possible.
+ Instruction *findInsertPt(Instruction *User, ArrayRef<Value*> Ops);
+
bool CanExpand(const SCEV* S);
Value *expandCheck(SCEVExpander &Expander, IRBuilder<> &Builder,
ICmpInst::Predicate Pred, const SCEV *LHS,
@@ -438,6 +444,14 @@
return Step->isOne() || (Step->isAllOnesValue() && EnableCountDownLoop);
}
+Instruction *LoopPredication::findInsertPt(Instruction *Use,
+ ArrayRef<Value*> Ops) {
+ for (Value *Op : Ops)
+ if (!L->isLoopInvariant(Op))
+ return Use;
+ return Preheader->getTerminator();
+}
+
bool LoopPredication::CanExpand(const SCEV* S) {
return SE->isLoopInvariant(S, L) && isSafeToExpand(S, *SE);
}
@@ -652,7 +666,7 @@
TotalWidened += NumWidened;
// Emit the new guard condition
- Builder.SetInsertPoint(Guard);
+ Builder.SetInsertPoint(findInsertPt(Guard, Checks));
Value *LastCheck = nullptr;
for (auto *Check : Checks)
if (!LastCheck)
@@ -684,7 +698,7 @@
TotalWidened += NumWidened;
// Emit the new guard condition
- Builder.SetInsertPoint(BI);
+ Builder.SetInsertPoint(findInsertPt(BI, Checks));
Value *LastCheck = nullptr;
for (auto *Check : Checks)
if (!LastCheck)
diff --git a/test/Transforms/LoopPredication/basic.ll b/test/Transforms/LoopPredication/basic.ll
index afb92f2..287c6d2 100644
--- a/test/Transforms/LoopPredication/basic.ll
+++ b/test/Transforms/LoopPredication/basic.ll
@@ -976,11 +976,11 @@
; CHECK-NEXT: [[TMP3:%.*]] = icmp ule i32 [[N]], [[LENGTH_1:%.*]]
; CHECK-NEXT: [[TMP4:%.*]] = icmp ult i32 0, [[LENGTH_1]]
; CHECK-NEXT: [[TMP5:%.*]] = and i1 [[TMP4]], [[TMP3]]
+; CHECK-NEXT: [[TMP6:%.*]] = and i1 [[TMP2]], [[TMP5]]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[LOOP]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[LOOP]] ], [ 0, [[LOOP_PREHEADER]] ]
-; CHECK-NEXT: [[TMP6:%.*]] = and i1 [[TMP2]], [[TMP5]]
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[TMP6]], i32 9) [ "deopt"() ]
; CHECK-NEXT: [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT: [[ARRAY_1_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY_1:%.*]], i64 [[I_I64]]
@@ -1048,12 +1048,12 @@
; CHECK-NEXT: [[TMP6:%.*]] = icmp ule i32 [[N]], [[LENGTH_1:%.*]]
; CHECK-NEXT: [[TMP7:%.*]] = icmp ult i32 0, [[LENGTH_1]]
; CHECK-NEXT: [[TMP8:%.*]] = and i1 [[TMP7]], [[TMP6]]
+; CHECK-NEXT: [[TMP9:%.*]] = and i1 [[TMP2]], [[TMP5]]
+; CHECK-NEXT: [[TMP10:%.*]] = and i1 [[TMP9]], [[TMP8]]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[LOOP]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[LOOP]] ], [ 0, [[LOOP_PREHEADER]] ]
-; CHECK-NEXT: [[TMP9:%.*]] = and i1 [[TMP2]], [[TMP5]]
-; CHECK-NEXT: [[TMP10:%.*]] = and i1 [[TMP9]], [[TMP8]]
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[TMP10]], i32 9) [ "deopt"() ]
; CHECK-NEXT: [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT: [[ARRAY_1_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY_1:%.*]], i64 [[I_I64]]
diff --git a/test/Transforms/LoopPredication/widened.ll b/test/Transforms/LoopPredication/widened.ll
index 569daff..38325cb 100644
--- a/test/Transforms/LoopPredication/widened.ll
+++ b/test/Transforms/LoopPredication/widened.ll
@@ -20,6 +20,7 @@
; CHECK-NEXT: [[TMP5:%.*]] = icmp ule i32 16, [[TMP4]]
; CHECK-NEXT: [[TMP6:%.*]] = icmp ult i32 [[OFFA]], [[LENGTHA]]
; CHECK-NEXT: [[TMP7:%.*]] = and i1 [[TMP6]], [[TMP5]]
+; CHECK-NEXT: [[TMP8:%.*]] = and i1 [[TMP3]], [[TMP7]]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
@@ -27,7 +28,6 @@
; CHECK-NEXT: [[IV_TRUNC_16:%.*]] = trunc i64 [[IV]] to i16
; CHECK-NEXT: [[INDEXA:%.*]] = add i32 [[IV_TRUNC_32]], [[OFFA]]
; CHECK-NEXT: [[INDEXB:%.*]] = add i16 [[IV_TRUNC_16]], [[OFFB]]
-; CHECK-NEXT: [[TMP8:%.*]] = and i1 [[TMP3]], [[TMP7]]
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[TMP8]], i32 9) [ "deopt"() ]
; CHECK-NEXT: [[INDEXA_EXT:%.*]] = zext i32 [[INDEXA]] to i64
; CHECK-NEXT: [[ADDRA:%.*]] = getelementptr inbounds i8, i8* [[ARRA]], i64 [[INDEXA_EXT]]
@@ -93,14 +93,14 @@
; CHECK-NEXT: [[TMP11:%.*]] = icmp ule i32 15, [[TMP10]]
; CHECK-NEXT: [[TMP12:%.*]] = icmp ult i32 [[OFFA]], [[LENGTHA]]
; CHECK-NEXT: [[TMP13:%.*]] = and i1 [[TMP12]], [[TMP11]]
+; CHECK-NEXT: [[TMP14:%.*]] = and i1 [[TMP4]], [[TMP8]]
+; CHECK-NEXT: [[TMP15:%.*]] = and i1 [[TMP14]], [[TMP13]]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
; CHECK-NEXT: [[IV_TRUNC:%.*]] = trunc i64 [[IV]] to i32
; CHECK-NEXT: [[INDEXA:%.*]] = add i32 [[IV_TRUNC]], [[OFFA]]
; CHECK-NEXT: [[INDEXB:%.*]] = add i32 [[IV_TRUNC]], [[OFFB]]
-; CHECK-NEXT: [[TMP14:%.*]] = and i1 [[TMP4]], [[TMP8]]
-; CHECK-NEXT: [[TMP15:%.*]] = and i1 [[TMP14]], [[TMP13]]
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[TMP15]], i32 9) [ "deopt"() ]
; CHECK-NEXT: [[INDEXA_EXT:%.*]] = zext i32 [[INDEXA]] to i64
; CHECK-NEXT: [[ADDRA:%.*]] = getelementptr inbounds i8, i8* [[ARRA]], i64 [[INDEXA_EXT]]
