Revert r286999 which caused buildbot test failures. Some testcases need to be made target specific.

llvm-svn: 287014

3 files changed, 7 insertions, 71 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index f22e8a69bdb..75677079e37 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -1048,16 +1048,17 @@ void Cost::RateRegister(const SCEV *Reg,
                         const Loop *L,
                         ScalarEvolution &SE, DominatorTree &DT) {
   if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Reg)) {
-    // If this is an addrec for another loop, it should be an invariant
-    // with respect to L since L is the innermost loop (at least
-    // for now LSR only handles innermost loops).
+    // If this is an addrec for another loop, don't second-guess its addrec phi
+    // nodes. LSR isn't currently smart enough to reason about more than one
+    // loop at a time. LSR has already run on inner loops, will not run on outer
+    // loops, and cannot be expected to change sibling loops.
     if (AR->getLoop() != L) {
       // If the AddRec exists, consider it's register free and leave it alone.
       if (isExistingPhi(AR, SE))
         return;
 
-      // Otherwise, it will be an invariant with respect to Loop L.
-      ++NumRegs;
+      // Otherwise, do not consider this formula at all.
+      Lose();
       return;
     }
     AddRecCost += 1; /// TODO: This should be a function of the stride.
diff --git a/llvm/test/CodeGen/X86/licm-nested.ll b/llvm/test/CodeGen/X86/licm-nested.ll
index 63e3c5c3b6b..42e6d12ec1e 100644
--- a/llvm/test/CodeGen/X86/licm-nested.ll
+++ b/llvm/test/CodeGen/X86/licm-nested.ll
@@ -1,5 +1,5 @@
 ; REQUIRES: asserts
-; RUN: llc -mtriple=x86_64-apple-darwin -march=x86-64 < %s -o /dev/null -stats -info-output-file - | grep "hoisted out of loops" | grep 5
+; RUN: llc -mtriple=x86_64-apple-darwin -march=x86-64 < %s -o /dev/null -stats -info-output-file - | grep "hoisted out of loops" | grep 4
 
 ; MachineLICM should be able to hoist the symbolic addresses out of
 ; the inner loops.
diff --git a/llvm/test/Transforms/LoopStrengthReduce/nested-loop.ll b/llvm/test/Transforms/LoopStrengthReduce/nested-loop.ll
deleted file mode 100644
index b563eb3ad99..00000000000
--- a/llvm/test/Transforms/LoopStrengthReduce/nested-loop.ll
+++ /dev/null
@@ -1,65 +0,0 @@
-; RUN: opt -loop-reduce -S < %s | FileCheck %s
-; Check when we use an outerloop induction variable inside of an innerloop
-; induction value expr, LSR can still choose to use single induction variable
-; for the innerloop and share it in multiple induction value exprs.
-
-target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
-target triple = "x86_64-unknown-linux-gnu"
-
-define void @foo(i32 %size, i32 %nsteps, i32 %hsize, i32* %lined, i8* %maxarray) {
-entry:
-  %cmp215 = icmp sgt i32 %size, 1
-  %t0 = zext i32 %size to i64
-  %t1 = sext i32 %nsteps to i64
-  %sub2 = sub i64 %t0, 2
-  br label %for.body
-
-for.body:                                         ; preds = %for.inc, %entry
-  %indvars.iv2 = phi i64 [ %indvars.iv.next3, %for.inc ], [ 0, %entry ]
-  %t2 = mul nsw i64 %indvars.iv2, %t0
-  br i1 %cmp215, label %for.body2.preheader, label %for.inc
-
-for.body2.preheader:                              ; preds = %for.body
-  br label %for.body2
-
-; Check LSR only generates one induction variable for for.body2 and the induction
-; variable will be shared by multiple array accesses.
-; CHECK: for.body2:
-; CHECK-NEXT: [[LSR:%[^,]+]] = phi i64 [ %lsr.iv.next, %for.body2 ], [ 0, %for.body2.preheader ]
-; CHECK-NOT:  = phi i64 [ {{.*}}, %for.body2 ], [ {{.*}}, %for.body2.preheader ]
-; CHECK:      [[SCEVGEP1:%[^,]+]] = getelementptr i8, i8* %maxarray, i64 [[LSR]]
-; CHECK:      [[SCEVGEP2:%[^,]+]] = getelementptr i8, i8* [[SCEVGEP1]], i64 1
-; CHECK:      {{.*}} = load i8, i8* [[SCEVGEP2]], align 1
-; CHECK:      [[SCEVGEP3:%[^,]+]] = getelementptr i8, i8* {{.*}}, i64 [[LSR]]
-; CHECK:      {{.*}} = load i8, i8* [[SCEVGEP3]], align 1
-; CHECK:      [[SCEVGEP4:%[^,]+]] = getelementptr i8, i8* {{.*}}, i64 [[LSR]]
-; CHECK:      store i8 {{.*}}, i8* [[SCEVGEP4]], align 1
-; CHECK:      br i1 %exitcond, label %for.body2, label %for.inc.loopexit
-
-for.body2:                                        ; preds = %for.body2.preheader, %for.body2
-  %indvars.iv = phi i64 [ 1, %for.body2.preheader ], [ %indvars.iv.next, %for.body2 ]
-  %arrayidx1 = getelementptr inbounds i8, i8* %maxarray, i64 %indvars.iv
-  %v1 = load i8, i8* %arrayidx1, align 1
-  %idx2 = add nsw i64 %indvars.iv, %sub2
-  %arrayidx2 = getelementptr inbounds i8, i8* %maxarray, i64 %idx2
-  %v2 = load i8, i8* %arrayidx2, align 1
-  %tmpv = xor i8 %v1, %v2
-  %t4 = add nsw i64 %t2, %indvars.iv
-  %add.ptr = getelementptr inbounds i8, i8* %maxarray, i64 %t4
-  store i8 %tmpv, i8* %add.ptr, align 1
-  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
-  %wide.trip.count = zext i32 %size to i64
-  %exitcond = icmp ne i64 %indvars.iv.next, %wide.trip.count
-  br i1 %exitcond, label %for.body2, label %for.inc.loopexit
-
-for.inc.loopexit:                                 ; preds = %for.body2
-  br label %for.inc
-
-for.inc:                                          ; preds = %for.inc.loopexit, %for.body
-  %indvars.iv.next3 = add nuw nsw i64 %indvars.iv2, 1
-  %cmp = icmp slt i64 %indvars.iv.next3, %t1
-  br i1 %cmp, label %for.body, label %for.end.loopexit
-
-for.end.loopexit:                                 ; preds = %for.inc
-  ret void
-}