[llvm] r252623 - Revert "Strip metadata when speculatively hoisting instructions"

Renato Golin via llvm-commits llvm-commits at lists.llvm.org
Tue Nov 10 10:01:16 PST 2015


Author: rengolin
Date: Tue Nov 10 12:01:16 2015
New Revision: 252623

URL: http://llvm.org/viewvc/llvm-project?rev=252623&view=rev
Log:
Revert "Strip metadata when speculatively hoisting instructions"

This reverts commit r252604, as it broke all ARM and AArch64 buildbots, as
well as some x86, et al.

Modified:
    llvm/trunk/lib/Analysis/LoopInfo.cpp
    llvm/trunk/lib/Transforms/Scalar/LICM.cpp
    llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
    llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/licm.ll
    llvm/trunk/test/Transforms/LICM/hoist-deref-load.ll
    llvm/trunk/test/Transforms/SimplifyCFG/SpeculativeExec.ll

Modified: llvm/trunk/lib/Analysis/LoopInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LoopInfo.cpp?rev=252623&r1=252622&r2=252623&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LoopInfo.cpp (original)
+++ llvm/trunk/lib/Analysis/LoopInfo.cpp Tue Nov 10 12:01:16 2015
@@ -120,13 +120,6 @@ bool Loop::makeLoopInvariant(Instruction
 
   // Hoist.
   I->moveBefore(InsertPt);
-
-  // There is possibility of hoisting this instruction above some arbitrary
-  // condition. Any metadata defined on it can be control dependent on this
-  // condition. Conservatively strip it here so that we don't give any wrong
-  // information to the optimizer.
-  I->dropUnknownNonDebugMetadata();
-
   Changed = true;
   return true;
 }

Modified: llvm/trunk/lib/Transforms/Scalar/LICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LICM.cpp?rev=252623&r1=252622&r2=252623&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LICM.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LICM.cpp Tue Nov 10 12:01:16 2015
@@ -672,10 +672,6 @@ static bool hoist(Instruction &I, BasicB
   // Move the new node to the Preheader, before its terminator.
   I.moveBefore(Preheader->getTerminator());
 
-  // Metadata can be dependent on the condition we are hoisting above.
-  // Conservatively strip all metadata on the instruction.
-  I.dropUnknownNonDebugMetadata();
-
   if (isa<LoadInst>(I)) ++NumMovedLoads;
   else if (isa<CallInst>(I)) ++NumMovedCalls;
   ++NumHoisted;

Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=252623&r1=252622&r2=252623&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Tue Nov 10 12:01:16 2015
@@ -1618,11 +1618,6 @@ static bool SpeculativelyExecuteBB(Branc
     SpeculatedStore->setOperand(0, S);
   }
 
-  // Metadata can be dependent on the condition we are hoisting above.
-  // Conservatively strip all metadata on the instruction.
-  for (auto &I: *ThenBB)
-    I.dropUnknownNonDebugMetadata();
-
   // Hoist the instructions.
   BB->getInstList().splice(BI->getIterator(), ThenBB->getInstList(),
                            ThenBB->begin(), std::prev(ThenBB->end()));

Modified: llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/licm.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/licm.ll?rev=252623&r1=252622&r2=252623&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/licm.ll (original)
+++ llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/licm.ll Tue Nov 10 12:01:16 2015
@@ -5,7 +5,7 @@
 
 ; CHECK: @foo
 ; CHECK:      entry:
-; CHECK-NEXT:   %tmp3 = load double*, double** @P
+; CHECK-NEXT:   %tmp3 = load double*, double** @P, !tbaa !0
 ; CHECK-NEXT:   br label %for.body
 
 @P = common global double* null

Modified: llvm/trunk/test/Transforms/LICM/hoist-deref-load.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LICM/hoist-deref-load.ll?rev=252623&r1=252622&r2=252623&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LICM/hoist-deref-load.ll (original)
+++ llvm/trunk/test/Transforms/LICM/hoist-deref-load.ll Tue Nov 10 12:01:16 2015
@@ -388,49 +388,5 @@ for.end:
   ret void
 }
 
-; In this test we should be able to only hoist load from %cptr. We can't hoist
-; load from %c because it's dereferenceability can depend on %cmp1 condition.
-; By moving it out of the loop we break this dependency and can not rely
-; on the dereferenceability anymore.
-; In other words this test checks that we strip dereferenceability  metadata
-; after hoisting an instruction.
-
-; CHECK-LABEL: @test10
-; CHECK: %c = load i32*, i32** %cptr
-; CHECK-NOT: dereferenceable
-; CHECK: if.then:
-; CHECK: load i32, i32* %c, align 4
-
-define void @test10(i32* noalias %a, i32* %b, i32** dereferenceable(8) %cptr, i32 %n) #0 {
-entry:
-  %cmp11 = icmp sgt i32 %n, 0
-  br i1 %cmp11, label %for.body, label %for.end
-
-for.body:                                         ; preds = %entry, %for.inc
-  %indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %entry ]
-  %arrayidx = getelementptr inbounds i32, i32* %a, i64 %indvars.iv
-  %0 = load i32, i32* %arrayidx, align 4
-  %cmp1 = icmp sgt i32 %0, 0
-  br i1 %cmp1, label %if.then, label %for.inc
-
-if.then:                                          ; preds = %for.body
-  %c = load i32*, i32** %cptr, !dereferenceable !0
-  %1 = load i32, i32* %c, align 4
-  %arrayidx3 = getelementptr inbounds i32, i32* %b, i64 %indvars.iv
-  %2 = load i32, i32* %arrayidx3, align 4
-  %mul = mul nsw i32 %2, %1
-  store i32 %mul, i32* %arrayidx, align 4
-  br label %for.inc
-
-for.inc:                                          ; preds = %for.body, %if.then
-  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
-  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
-  %exitcond = icmp eq i32 %lftr.wideiv, %n
-  br i1 %exitcond, label %for.end, label %for.body
-
-for.end:                                          ; preds = %for.inc, %entry
-  ret void
-}
-
 attributes #0 = { nounwind uwtable }
 !0 = !{i64 4}

Modified: llvm/trunk/test/Transforms/SimplifyCFG/SpeculativeExec.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyCFG/SpeculativeExec.ll?rev=252623&r1=252622&r2=252623&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/SimplifyCFG/SpeculativeExec.ll (original)
+++ llvm/trunk/test/Transforms/SimplifyCFG/SpeculativeExec.ll Tue Nov 10 12:01:16 2015
@@ -69,29 +69,3 @@ end:
 
   ret i8* %x10
 }
-
-define i32* @test5(i32 %a, i32 %b, i32 %c, i32* dereferenceable(10) %ptr1,
-                  i32* dereferenceable(10) %ptr2, i32** dereferenceable(10) %ptr3) nounwind {
-; CHECK-LABEL: @test5(
-entry:
-        %tmp1 = icmp eq i32 %b, 0
-        br i1 %tmp1, label %bb1, label %bb3
-
-bb1:            ; preds = %entry
-	%tmp2 = icmp sgt i32 %c, 1
-	br i1 %tmp2, label %bb2, label %bb3
-; CHECK: bb1:
-; CHECK-NEXT: icmp sgt i32 %c, 1
-; CHECK-NEXT: load i32*, i32** %ptr3
-; CHECK-NOT: dereferenceable
-; CHECK-NEXT: select i1 %tmp2, i32* %tmp3, i32* %ptr2
-; CHECK-NEXT: ret i32* %tmp3.ptr2
-
-bb2:		; preds = bb1
-        %tmp3 = load i32*, i32** %ptr3, !dereferenceable !{i64 10}
-	br label %bb3
-
-bb3:		; preds = %bb2, %entry
-	%tmp4 = phi i32* [ %ptr1, %entry ], [ %ptr2, %bb1 ], [ %tmp3, %bb2 ]
-	ret i32* %tmp4
-}




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