Revert "Temporarily Revert "Add basic loop fusion pass.""

The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552

1 files changed, 165 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopInstSimplify/basic.ll b/llvm/test/Transforms/LoopInstSimplify/basic.ll
new file mode 100644
index 00000000000..d6f177f07aa
--- /dev/null
+++ b/llvm/test/Transforms/LoopInstSimplify/basic.ll
@@ -0,0 +1,165 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S %s -passes=loop-instsimplify | FileCheck %s
+; RUN: opt -S %s -passes=loop-instsimplify -enable-mssa-loop-dependency=true -verify-memoryssa | FileCheck %s
+
+; Test very basic folding and propagation occurs within a loop body. This should
+; collapse to the loop iteration structure and the LCSSA PHI node.
+define i32 @test1(i32 %n, i32 %x) {
+; CHECK-LABEL: @test1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[I_NEXT]] = add nsw i32 [[I]], 1
+; CHECK-NEXT:    [[I_CMP:%.*]] = icmp slt i32 [[I_NEXT]], [[N:%.*]]
+; CHECK-NEXT:    br i1 [[I_CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[X_LCSSA:%.*]] = phi i32 [ [[X:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    ret i32 [[X_LCSSA]]
+;
+entry:
+  br label %loop
+
+loop:
+  %i = phi i32 [ 0, %entry ], [ %i.next, %loop ]
+  %x.add = add nsw i32 %x, 0
+  %x.sub = sub i32 %x.add, 0
+  %x.and = and i32 %x.sub, -1
+  %i.next = add nsw i32 %i, 1
+  %i.cmp = icmp slt i32 %i.next, %n
+  br i1 %i.cmp, label %loop, label %exit
+
+exit:
+  %x.lcssa = phi i32 [ %x.and, %loop ]
+  ret i32 %x.lcssa
+}
+
+; Test basic loop structure that still has a simplification feed a prior PHI.
+define i32 @test2(i32 %n, i32 %x) {
+; CHECK-LABEL: @test2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[I_NEXT]] = add nsw i32 [[I]], 1
+; CHECK-NEXT:    [[I_CMP:%.*]] = icmp slt i32 [[I_NEXT]], [[N:%.*]]
+; CHECK-NEXT:    br i1 [[I_CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[X_LCSSA:%.*]] = phi i32 [ [[X:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    ret i32 [[X_LCSSA]]
+;
+entry:
+  br label %loop
+
+loop:
+  %i = phi i32 [ 0, %entry ], [ %i.next, %loop ]
+  %x.loop = phi i32 [ %x, %entry ], [ %x.next, %loop ]
+  %x.next = add nsw i32 %x.loop, 0
+  %i.next = add nsw i32 %i, 1
+  %i.cmp = icmp slt i32 %i.next, %n
+  br i1 %i.cmp, label %loop, label %exit
+
+exit:
+  %x.lcssa = phi i32 [ %x.loop, %loop ]
+  ret i32 %x.lcssa
+}
+
+; Test a diamond CFG with inner PHI nodes.
+define i32 @test3(i32 %n, i32 %x) {
+; CHECK-LABEL: @test3(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[X_CMP:%.*]] = icmp slt i32 [[I]], 42
+; CHECK-NEXT:    br i1 [[X_CMP]], label [[LOOP_LHS:%.*]], label [[LOOP_RHS:%.*]]
+; CHECK:       loop.lhs:
+; CHECK-NEXT:    br label [[LOOP_LATCH]]
+; CHECK:       loop.rhs:
+; CHECK-NEXT:    br label [[LOOP_LATCH]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    [[I_NEXT]] = add nsw i32 [[I]], 1
+; CHECK-NEXT:    [[I_CMP:%.*]] = icmp slt i32 [[I_NEXT]], [[N:%.*]]
+; CHECK-NEXT:    br i1 [[I_CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[X_LCSSA:%.*]] = phi i32 [ [[X:%.*]], [[LOOP_LATCH]] ]
+; CHECK-NEXT:    ret i32 [[X_LCSSA]]
+;
+entry:
+  br label %loop
+
+loop:
+  %i = phi i32 [ 0, %entry ], [ %i.next, %loop.latch ]
+  %x.loop = phi i32 [ %x, %entry ], [ %x.phi, %loop.latch ]
+  %x.add = add nsw i32 %x.loop, 0
+  %x.cmp = icmp slt i32 %i, 42
+  br i1 %x.cmp, label %loop.lhs, label %loop.rhs
+
+loop.lhs:
+  %x.l.add = add nsw i32 %x.add, 0
+  br label %loop.latch
+
+loop.rhs:
+  %x.r.sub = sub nsw i32 %x.add, 0
+  br label %loop.latch
+
+loop.latch:
+  %x.phi = phi i32 [ %x.l.add, %loop.lhs ], [ %x.r.sub, %loop.rhs ]
+  %i.next = add nsw i32 %i, 1
+  %i.cmp = icmp slt i32 %i.next, %n
+  br i1 %i.cmp, label %loop, label %exit
+
+exit:
+  %x.lcssa = phi i32 [ %x.loop, %loop.latch ]
+  ret i32 %x.lcssa
+}
+
+; Test an inner loop that is only simplified when processing the outer loop, and
+; an outer loop only simplified when processing the inner loop.
+define i32 @test4(i32 %n, i32 %m, i32 %x) {
+; CHECK-LABEL: @test4(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    br label [[LOOP_INNER:%.*]]
+; CHECK:       loop.inner:
+; CHECK-NEXT:    [[J:%.*]] = phi i32 [ 0, [[LOOP]] ], [ [[J_NEXT:%.*]], [[LOOP_INNER]] ]
+; CHECK-NEXT:    [[J_NEXT]] = add nsw i32 [[J]], 1
+; CHECK-NEXT:    [[J_CMP:%.*]] = icmp slt i32 [[J_NEXT]], [[M:%.*]]
+; CHECK-NEXT:    br i1 [[J_CMP]], label [[LOOP_INNER]], label [[LOOP_LATCH]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    [[I_NEXT]] = add nsw i32 [[I]], 1
+; CHECK-NEXT:    [[I_CMP:%.*]] = icmp slt i32 [[I_NEXT]], [[N:%.*]]
+; CHECK-NEXT:    br i1 [[I_CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[X_LCSSA:%.*]] = phi i32 [ [[X:%.*]], [[LOOP_LATCH]] ]
+; CHECK-NEXT:    ret i32 [[X_LCSSA]]
+;
+entry:
+  br label %loop
+
+loop:
+  %i = phi i32 [ 0, %entry ], [ %i.next, %loop.latch ]
+  %x.loop = phi i32 [ %x, %entry ], [ %x.inner.lcssa, %loop.latch ]
+  %x.add = add nsw i32 %x.loop, 0
+  br label %loop.inner
+
+loop.inner:
+  %j = phi i32 [ 0, %loop ], [ %j.next, %loop.inner ]
+  %x.inner.loop = phi i32 [ %x.add, %loop ], [ %x.inner.add, %loop.inner ]
+  %x.inner.add = add nsw i32 %x.inner.loop, 0
+  %j.next = add nsw i32 %j, 1
+  %j.cmp = icmp slt i32 %j.next, %m
+  br i1 %j.cmp, label %loop.inner, label %loop.latch
+
+loop.latch:
+  %x.inner.lcssa = phi i32 [ %x.inner.loop, %loop.inner ]
+  %i.next = add nsw i32 %i, 1
+  %i.cmp = icmp slt i32 %i.next, %n
+  br i1 %i.cmp, label %loop, label %exit
+
+exit:
+  %x.lcssa = phi i32 [ %x.loop, %loop.latch ]
+  ret i32 %x.lcssa
+}