RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-23 11:13:28 +01:00
Code Issues Projects Releases Wiki Activity

[LoopPred] Fix a blatantly obvious bug in r358684

Browse Source 
The bug is that I didn't check whether the operand of the invariant_loads were themselves invariant.  I don't know how this got missed in the patch and review.  I even had an unreduced test case locally, and I remember handling this case, but I must have lost it in one of the rebases.  Oops.

llvm-svn: 358688
This commit is contained in:
Philip Reames 2019-04-18 17:01:19 +00:00
parent 8cd56145bc
commit 2b301a9a7e
2 changed files with 65 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
lib/Transforms/Scalar/LoopPredication.cpp
View File

@ -510,7 +510,7 @@ bool LoopPredication::isLoopInvariantValue(const SCEV* S) {
// TODO: This should be sunk inside SCEV.
if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S))
if (const auto *LI = dyn_cast<LoadInst>(U->getValue()))
if (LI->isUnordered())
if (LI->isUnordered() && L->hasLoopInvariantOperands(LI))
if (AA->pointsToConstantMemory(LI->getOperand(0)) ||
LI->getMetadata(LLVMContext::MD_invariant_load) != nullptr)
return true;

64
test/Transforms/LoopPredication/invariant_load.ll
View File

@ -126,6 +126,70 @@ exit:
ret i32 %result
}
; Case where we have an invariant load, but it's not loading from a loop
; invariant location.
define i32 @neg_varying_invariant_load_op(i32* %array, i32* %lengths, i32 %n) {
; CHECK-LABEL: @neg_varying_invariant_load_op(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP5:%.*]] = icmp eq i32 [[N:%.*]], 0
; CHECK-NEXT: br i1 [[TMP5]], label [[EXIT:%.*]], label [[LOOP_PREHEADER:%.*]]
; CHECK: loop.preheader:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[LOOP]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[LOOP]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT: [[UNKNOWN:%.*]] = load volatile i1, i1* @UNKNOWN
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[UNKNOWN]]) [ "deopt"() ]
; CHECK-NEXT: [[LENGTH_ADDR:%.*]] = getelementptr i32, i32* [[LENGTHS:%.*]], i32 [[I]]
; CHECK-NEXT: [[LEN:%.*]] = load i32, i32* [[LENGTH_ADDR]], align 4, !invariant.load !0
; CHECK-NEXT: [[WITHIN_BOUNDS:%.*]] = icmp ult i32 [[I]], [[LEN]]
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[WITHIN_BOUNDS]], i32 9) [ "deopt"() ]
; CHECK-NEXT: [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT: [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I_I64]]
; CHECK-NEXT: [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT: [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT: [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT: [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N]]
; CHECK-NEXT: br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT_LOOPEXIT:%.*]]
; CHECK: exit.loopexit:
; CHECK-NEXT: [[LOOP_ACC_NEXT_LCSSA:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[LOOP]] ]
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
; CHECK-NEXT: [[RESULT:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[LOOP_ACC_NEXT_LCSSA]], [[EXIT_LOOPEXIT]] ]
; CHECK-NEXT: ret i32 [[RESULT]]
;
entry:
%tmp5 = icmp eq i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
br label %loop
loop:
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ 0, %loop.preheader ]
%unknown = load volatile i1, i1* @UNKNOWN
call void (i1, ...) @llvm.experimental.guard(i1 %unknown) [ "deopt"() ]
%length.addr = getelementptr i32, i32* %lengths, i32 %i
%len = load i32, i32* %length.addr, align 4, !invariant.load !{}
%within.bounds = icmp ult i32 %i, %len
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
; This is a case where moving the load which provides the limit for the latch
; would be invalid, so we can't preform the tempting transform. Loading the
; latch limit may fault since we could always fail the guard.