[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 8487278d3d616c0612b8bf193054466099a682f2..3b27364cf5ec20ade3ca07ee361a12bdc919c399 100644 (file)
--- a/lib/Transforms/Scalar/LoopPredication.cpp
+++ b/lib/Transforms/Scalar/LoopPredication.cpp
@@ -264,6 +264,12 @@ class LoopPredication {
 
   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 @@ bool LoopPredication::isSupportedStep(const SCEV* Step) {
   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 @@ bool LoopPredication::widenGuardConditions(IntrinsicInst *Guard,
   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 @@ bool LoopPredication::widenWidenableBranchGuardConditions(
   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 afb92f263cb656f14d1b300ce1d258b05bd9a762..287c6d20be7e77051338fc97234f40de7f3265c9 100644 (file)
--- a/test/Transforms/LoopPredication/basic.ll
+++ b/test/Transforms/LoopPredication/basic.ll
@@ -976,11 +976,11 @@ define i32 @two_range_checks(i32* %array.1, i32 %length.1,
 ; 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 @@ define i32 @three_range_checks(i32* %array.1, i32 %length.1,
 ; 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 569daff90810040e1c426f56adc78b1d26f8b6c3..38325cbec50c606b98162e9ad303e4e7e50d9031 100644 (file)
--- a/test/Transforms/LoopPredication/widened.ll
+++ b/test/Transforms/LoopPredication/widened.ll
@@ -20,6 +20,7 @@ define i64 @iv_wider_type_rc_two_narrow_types(i32 %offA, i16 %offB, i8* %arrA, i
 ; 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 @@ define i64 @iv_wider_type_rc_two_narrow_types(i32 %offA, i16 %offB, i8* %arrA, i
 ; 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 @@ define i64 @iv_rc_different_types(i32 %offA, i32 %offB, i8* %arrA, i8* %arrB, i6
 ; 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]]