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llvm-mirror/test/Transforms/LoopSimplify/pr28272.ll

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[LoopSimplify] Rebuild LCSSA for the inner loop after separating nested loops. Summary: This hopefully fixes PR28825. The problem now was that a value from the original loop was used in a subloop, which became a sibling after separation. While a subloop doesn't need an lcssa phi node, a sibling does, and that's where we broke LCSSA. The most natural way to fix this now is to simply call formLCSSA on the original loop: it'll do what we've been doing before plus it'll cover situations described above. I think we don't need to run formLCSSARecursively here, and we have an assert to verify this (I've tried testing it on LLVM testsuite + SPECs). I'd be happy to be corrected here though. I also changed a run line in the test from '-lcssa -loop-unroll' to '-lcssa -loop-simplify -indvars', because it exercises LCSSA preservation to the same extent, but also makes less unrelated transformation on the CFG, which makes it easier to verify. Reviewers: chandlerc, sanjoy, silvas Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D23288 llvm-svn: 278173
2016-08-10 00:44:56 +02:00
; RUN: opt < %s -lcssa -loop-simplify -indvars -S | FileCheck %s
Revert "Revert r275883 and r275891. They seem to cause PR28608." This reverts commit r276064, and thus reapplies r275891 and r275883 with a fix for PR28608. llvm-svn: 276077
2016-07-20 03:55:27 +02:00
target triple = "x86_64-unknown-linux-gnu"
Revert "Revert "[LoopSimplify] Fix updating LCSSA after separating nested loops."" This reverts commit r277901. Reaaply the commit as it looks like it has nothing to do with the bots failures. llvm-svn: 277946
2016-08-07 03:56:54 +02:00
; PR28272, PR28825
Revert "Revert r275883 and r275891. They seem to cause PR28608." This reverts commit r276064, and thus reapplies r275891 and r275883 with a fix for PR28608. llvm-svn: 276077
2016-07-20 03:55:27 +02:00
; When LoopSimplify separates nested loops, it might break LCSSA form: values
; from the original loop might be used in the outer loop. This test invokes
; loop-unroll, which calls loop-simplify before itself. If LCSSA is broken
; after loop-simplify, we crash on assertion.
; CHECK-LABEL: @foo
define void @foo() {
entry:
br label %header
header:
br label %loop1
loop1:
br i1 true, label %loop1, label %bb43
bb43:
%a = phi i32 [ undef, %loop1 ], [ 0, %bb45 ], [ %a, %bb54 ]
%b = phi i32 [ 0, %loop1 ], [ 1, %bb54 ], [ %c, %bb45 ]
br i1 true, label %bb114, label %header
bb114:
%c = add i32 0, 1
%d = add i32 0, 1
br i1 true, label %bb45, label %bb54
bb45:
%x = add i32 %d, 0
br label %bb43
bb54:
br label %bb43
}
; CHECK-LABEL: @foo2
define void @foo2() {
entry:
br label %outer
outer.loopexit:
br label %outer
outer:
br label %loop1
loop1:
br i1 true, label %loop1, label %loop2.preheader
loop2.preheader:
%a.ph = phi i32 [ undef, %loop1 ]
%b.ph = phi i32 [ 0, %loop1 ]
br label %loop2
loop2:
%a = phi i32 [ 0, %loop2.if.true ], [ %a, %loop2.if.false ], [ %a.ph, %loop2.preheader ], [0, %bb]
%b = phi i32 [ 1, %loop2.if.false ], [ %c, %loop2.if.true ], [ %b.ph, %loop2.preheader ], [%c, %bb]
br i1 true, label %loop2.if, label %outer.loopexit
loop2.if:
%c = add i32 0, 1
switch i32 undef, label %loop2.if.false [i32 0, label %loop2.if.true
i32 1, label %bb]
loop2.if.true:
br i1 undef, label %loop2, label %bb
loop2.if.false:
br label %loop2
bb:
br label %loop2
}
Revert "Revert "[LoopSimplify] Fix updating LCSSA after separating nested loops."" This reverts commit r277901. Reaaply the commit as it looks like it has nothing to do with the bots failures. llvm-svn: 277946
2016-08-07 03:56:54 +02:00
; When LoopSimplify separates nested loops, it might break LCSSA form: values
; from the original loop might be used in exit blocks of the outer loop.
; CHECK-LABEL: @foo3
define void @foo3() {
entry:
br label %bb1
bb1:
br i1 undef, label %bb2, label %bb1
bb2:
%a = phi i32 [ undef, %bb1 ], [ %a, %bb3 ], [ undef, %bb5 ]
br i1 undef, label %bb3, label %bb1
bb3:
%b = load i32*, i32** undef
br i1 undef, label %bb2, label %bb4
bb4:
br i1 undef, label %bb5, label %bb6
bb5:
br i1 undef, label %bb2, label %bb4
bb6:
br i1 undef, label %bb_end, label %bb1
bb_end:
%x = getelementptr i32, i32* %b
br label %bb_end
}
[LoopSimplify] Rebuild LCSSA for the inner loop after separating nested loops. Summary: This hopefully fixes PR28825. The problem now was that a value from the original loop was used in a subloop, which became a sibling after separation. While a subloop doesn't need an lcssa phi node, a sibling does, and that's where we broke LCSSA. The most natural way to fix this now is to simply call formLCSSA on the original loop: it'll do what we've been doing before plus it'll cover situations described above. I think we don't need to run formLCSSARecursively here, and we have an assert to verify this (I've tried testing it on LLVM testsuite + SPECs). I'd be happy to be corrected here though. I also changed a run line in the test from '-lcssa -loop-unroll' to '-lcssa -loop-simplify -indvars', because it exercises LCSSA preservation to the same extent, but also makes less unrelated transformation on the CFG, which makes it easier to verify. Reviewers: chandlerc, sanjoy, silvas Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D23288 llvm-svn: 278173
2016-08-10 00:44:56 +02:00
; When LoopSimplify separates nested loops, it might break LCSSA form: values
; from the original loop might occur in a loop, which is now a sibling of the
; original loop (before separating it was a subloop of the original loop, and
; thus didn't require an lcssa phi nodes).
; CHECK-LABEL: @foo4
define void @foo4() {
bb1:
br label %bb2
; CHECK: bb2.loopexit:
bb2.loopexit: ; preds = %bb3
%i.ph = phi i32 [ 0, %bb3 ]
br label %bb2
; CHECK: bb2.outer:
; CHECK: bb2:
bb2: ; preds = %bb2.loopexit, %bb2, %bb1
%i = phi i32 [ 0, %bb1 ], [ %i, %bb2 ], [ %i.ph, %bb2.loopexit ]
%x = load i32, i32* undef, align 8
br i1 undef, label %bb2, label %bb3.preheader
; CHECK: bb3.preheader:
bb3.preheader: ; preds = %bb2
; CHECK: %x.lcssa = phi i32 [ %x, %bb2 ]
br label %bb3
bb3: ; preds = %bb3.preheader, %bb3
%y = add i32 2, %x
br i1 true, label %bb2.loopexit, label %bb3
}
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