mkazantsev created this revision.
mkazantsev added reviewers: nikic, lebedev.ri, fhahn, reames, skatkov.
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This allows us to support more cases when facts are known from dominating guards.
https://reviews.llvm.org/D148098
Files:
llvm/lib/Analysis/ScalarEvolution.cpp
llvm/test/Transforms/LICM/hoist-add-sub.ll
Index: llvm/test/Transforms/LICM/hoist-add-sub.ll
===================================================================
--- llvm/test/Transforms/LICM/hoist-add-sub.ll
+++ llvm/test/Transforms/LICM/hoist-add-sub.ll
@@ -215,7 +215,7 @@
ret i32 -1
}
-; TODO: x + iv < 4 ==> iv < 4 - x
+; x + iv < 4 ==> iv < 4 - x
define i32 @test_02a(ptr %p, ptr %x_p, ptr %length_p) {
; CHECK-LABEL: define i32 @test_02a
; CHECK-SAME: (ptr [[P:%.*]], ptr [[X_P:%.*]], ptr [[LENGTH_P:%.*]]) {
@@ -227,11 +227,11 @@
; CHECK-NEXT: [[PRECOND:%.*]] = and i1 [[PRECOND_1]], [[PRECOND_2]]
; CHECK-NEXT: br i1 [[PRECOND]], label [[LOOP_PREHEADER:%.*]], label [[FAILED:%.*]]
; CHECK: loop.preheader:
+; CHECK-NEXT: [[INVARIANT_OP:%.*]] = sub nsw i32 4, [[X]]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV:%.*]] = phi i32 [ [[IV_NEXT:%.*]], [[BACKEDGE:%.*]] ], [ 0, [[LOOP_PREHEADER]] ]
-; CHECK-NEXT: [[ARITH:%.*]] = add nsw i32 [[X]], [[IV]]
-; CHECK-NEXT: [[X_CHECK:%.*]] = icmp slt i32 [[ARITH]], 4
+; CHECK-NEXT: [[X_CHECK:%.*]] = icmp slt i32 [[IV]], [[INVARIANT_OP]]
; CHECK-NEXT: br i1 [[X_CHECK]], label [[OUT_OF_BOUNDS:%.*]], label [[BACKEDGE]]
; CHECK: backedge:
; CHECK-NEXT: [[EL_PTR:%.*]] = getelementptr i32, ptr [[P]], i32 [[IV]]
@@ -328,7 +328,7 @@
ret i32 -1
}
-; TODO: iv - x < 4 ==> iv < 4 + x
+; iv - x < 4 ==> iv < 4 + x
define i32 @test_03a(ptr %p, ptr %x_p, ptr %length_p) {
; CHECK-LABEL: define i32 @test_03a
; CHECK-SAME: (ptr [[P:%.*]], ptr [[X_P:%.*]], ptr [[LENGTH_P:%.*]]) {
@@ -340,11 +340,11 @@
; CHECK-NEXT: [[PRECOND:%.*]] = and i1 [[PRECOND_1]], [[PRECOND_2]]
; CHECK-NEXT: br i1 [[PRECOND]], label [[LOOP_PREHEADER:%.*]], label [[FAILED:%.*]]
; CHECK: loop.preheader:
+; CHECK-NEXT: [[INVARIANT_OP:%.*]] = add nsw i32 4, [[X]]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV:%.*]] = phi i32 [ [[IV_NEXT:%.*]], [[BACKEDGE:%.*]] ], [ 0, [[LOOP_PREHEADER]] ]
-; CHECK-NEXT: [[ARITH:%.*]] = sub nsw i32 [[IV]], [[X]]
-; CHECK-NEXT: [[X_CHECK:%.*]] = icmp slt i32 [[ARITH]], 4
+; CHECK-NEXT: [[X_CHECK:%.*]] = icmp slt i32 [[IV]], [[INVARIANT_OP]]
; CHECK-NEXT: br i1 [[X_CHECK]], label [[OUT_OF_BOUNDS:%.*]], label [[BACKEDGE]]
; CHECK: backedge:
; CHECK-NEXT: [[EL_PTR:%.*]] = getelementptr i32, ptr [[P]], i32 [[IV]]
@@ -441,7 +441,7 @@
ret i32 -1
}
-; TODO: iv + x < 4 ==> iv < 4 - x
+; iv + x < 4 ==> iv < 4 - x
define i32 @test_04a(ptr %p, ptr %x_p, ptr %length_p) {
; CHECK-LABEL: define i32 @test_04a
; CHECK-SAME: (ptr [[P:%.*]], ptr [[X_P:%.*]], ptr [[LENGTH_P:%.*]]) {
@@ -453,11 +453,11 @@
; CHECK-NEXT: [[PRECOND:%.*]] = and i1 [[PRECOND_1]], [[PRECOND_2]]
; CHECK-NEXT: br i1 [[PRECOND]], label [[LOOP_PREHEADER:%.*]], label [[FAILED:%.*]]
; CHECK: loop.preheader:
+; CHECK-NEXT: [[INVARIANT_OP:%.*]] = sub nsw i32 4, [[X]]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV:%.*]] = phi i32 [ [[IV_NEXT:%.*]], [[BACKEDGE:%.*]] ], [ 0, [[LOOP_PREHEADER]] ]
-; CHECK-NEXT: [[ARITH:%.*]] = add nsw i32 [[IV]], [[X]]
-; CHECK-NEXT: [[X_CHECK:%.*]] = icmp slt i32 [[ARITH]], 4
+; CHECK-NEXT: [[X_CHECK:%.*]] = icmp slt i32 [[IV]], [[INVARIANT_OP]]
; CHECK-NEXT: br i1 [[X_CHECK]], label [[OUT_OF_BOUNDS:%.*]], label [[BACKEDGE]]
; CHECK: backedge:
; CHECK-NEXT: [[EL_PTR:%.*]] = getelementptr i32, ptr [[P]], i32 [[IV]]
Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -2340,6 +2340,8 @@
// Can we use context to prove the fact we need?
if (!CtxI)
return false;
+ if (auto *L = LI.getLoopFor(CtxI->getParent()))
+ B = applyLoopGuards(B, L);
// If result of operation in wide type is between narrow min/max extended to
// wide type, it means that the computation was without overflow.
const SCEV *NarrowMin =
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