Reapply r141870, SCEV expansion of post-inc.

Speculatively reapply to see if this test case still crashes on
linux. I may have fixed it in my last checkin.

llvm-svn: 141895
This commit is contained in:
Andrew Trick 2011-10-13 21:55:29 +00:00
parent ebe6067a8c
commit 870c1a3f15
2 changed files with 125 additions and 2 deletions

View File

@ -1120,6 +1120,14 @@ Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
BasicBlock *LatchBlock = L->getLoopLatch();
assert(LatchBlock && "PostInc mode requires a unique loop latch!");
Result = PN->getIncomingValueForBlock(LatchBlock);
// For an expansion to use the postinc form, the client must call
// expandCodeFor with an InsertPoint that is either outside the PostIncLoop
// or dominated by IVIncInsertPos.
assert((!isa<Instruction>(Result) ||
SE.DT->dominates(cast<Instruction>(Result),
Builder.GetInsertPoint())) &&
"postinc expansion does not dominate use");
}
// Re-apply any non-loop-dominating scale.
@ -1410,8 +1418,12 @@ Value *SCEVExpander::expand(const SCEV *S) {
Value *V = visit(S);
// Remember the expanded value for this SCEV at this location.
if (PostIncLoops.empty())
InsertedExpressions[std::make_pair(S, InsertPt)] = V;
//
// This is independent of PostIncLoops. The mapped value simply materializes
// the expression at this insertion point. If the mapped value happened to be
// a postinc expansion, it could be reused by a non postinc user, but only if
// its insertion point was already at the head of the loop.
InsertedExpressions[std::make_pair(S, InsertPt)] = V;
restoreInsertPoint(SaveInsertBB, SaveInsertPt);
return V;

View File

@ -0,0 +1,111 @@
; RUN: opt -loop-reduce -S < %s | FileCheck %s
;
; Test TransformForPostIncUse and LSR's expansion of expressions in
; post-inc form to ensure the implementation can handle expressions
; DAGs, not just trees.
target triple = "x86_64-apple-darwin"
; Verify that -loop-reduce runs without "hanging" and reuses post-inc
; expansions.
; CHECK: @test
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK: icmp
; CHECK-NOT: icmp
define void @test(i8* %base, i32 %a0) nounwind {
entry:
br label %bb1
bb1:
%n0 = sub i32 0, %a0
%t0 = icmp ugt i32 %n0, -4
%m0 = select i1 %t0, i32 %n0, i32 -4
%a1 = add i32 %m0, %a0
%n1 = sub i32 0, %a1
%t1 = icmp ugt i32 %n1, -4
%m1 = select i1 %t1, i32 %n1, i32 -4
%a2 = add i32 %m1, %a1
%n2 = sub i32 0, %a2
%t2 = icmp ugt i32 %n2, -4
%m2 = select i1 %t2, i32 %n2, i32 -4
%a3 = add i32 %m2, %a2
%n3 = sub i32 0, %a3
%t3 = icmp ugt i32 %n3, -4
%m3 = select i1 %t3, i32 %n3, i32 -4
%a4 = add i32 %m3, %a3
%n4 = sub i32 0, %a4
%t4 = icmp ugt i32 %n4, -4
%m4 = select i1 %t4, i32 %n4, i32 -4
%a5 = add i32 %m4, %a4
%n5 = sub i32 0, %a5
%t5 = icmp ugt i32 %n5, -4
%m5 = select i1 %t5, i32 %n5, i32 -4
%a6 = add i32 %m5, %a5
%n6 = sub i32 0, %a6
%t6 = icmp ugt i32 %n6, -4
%m6 = select i1 %t6, i32 %n6, i32 -4
%a7 = add i32 %m6, %a6
%n7 = sub i32 0, %a7
%t7 = icmp ugt i32 %n7, -4
%m7 = select i1 %t7, i32 %n7, i32 -4
%a8 = add i32 %m7, %a7
%n8 = sub i32 0, %a8
%t8 = icmp ugt i32 %n8, -4
%m8 = select i1 %t8, i32 %n8, i32 -4
%a9 = add i32 %m8, %a8
%n9 = sub i32 0, %a9
%t9 = icmp ugt i32 %n9, -4
%m9 = select i1 %t9, i32 %n9, i32 -4
%a10 = add i32 %m9, %a9
%n10 = sub i32 0, %a10
%t10 = icmp ugt i32 %n10, -4
%m10 = select i1 %t10, i32 %n10, i32 -4
%a11 = add i32 %m10, %a10
%n11 = sub i32 0, %a11
%t11 = icmp ugt i32 %n11, -4
%m11 = select i1 %t11, i32 %n11, i32 -4
%a12 = add i32 %m11, %a11
%n12 = sub i32 0, %a12
%t12 = icmp ugt i32 %n12, -4
%m12 = select i1 %t12, i32 %n12, i32 -4
%a13 = add i32 %m12, %a12
%n13 = sub i32 0, %a13
%t13 = icmp ugt i32 %n13, -4
%m13 = select i1 %t13, i32 %n13, i32 -4
%a14 = add i32 %m13, %a13
%n14 = sub i32 0, %a14
%t14 = icmp ugt i32 %n14, -4
%m14 = select i1 %t14, i32 %n14, i32 -4
%a15 = add i32 %m14, %a14
%n15 = sub i32 0, %a15
%t15 = icmp ugt i32 %n15, -4
%m15 = select i1 %t15, i32 %n15, i32 -4
%a16 = add i32 %m15, %a15
%gep = getelementptr i8* %base, i32 %a16
%ofs = add i32 %a16, 4
%limit = getelementptr i8* %base, i32 %ofs
br label %loop
loop:
%iv = phi i8* [ %gep, %bb1 ], [ %inc, %loop ]
%inc = getelementptr inbounds i8* %iv, i64 1
%exitcond = icmp eq i8* %inc, %limit
br i1 %exitcond, label %loop, label %exit
exit:
ret void
}