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author | Max Kazantsev <max.kazantsev@azul.com> | 2017-11-22 06:21:39 +0000 |
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committer | Max Kazantsev <max.kazantsev@azul.com> | 2017-11-22 06:21:39 +0000 |
commit | f66b47b32879fceffde1fe1511500ae3ce749667 (patch) | |
tree | 25ac2327091a39251f58000ee92b907d70f22892 /test/Analysis | |
parent | 882fbe3d4ca592cdc6be84327ff21d691df5d0d3 (diff) |
[SCEV] Strengthen variance condition in calculateLoopDisposition
Given loops `L1` and `L2` with AddRecs `AR1` and `AR2` varying in them respectively.
When identifying loop disposition of `AR2` w.r.t. `L1`, we only say that it is varying if
`L1` contains `L2`. But there is also a possible situation where `L1` and `L2` are
consecutive sibling loops within the parent loop. In this case, `AR2` is also varying
w.r.t. `L1`, but we don't correctly identify it.
It can lead, for exaple, to attempt of incorrect folding. Consider:
AR1 = {a,+,b}<L1>
AR2 = {c,+,d}<L2>
EXAR2 = sext(AR1)
MUL = mul AR1, EXAR2
If we incorrectly assume that `EXAR2` is invariant w.r.t. `L1`, we can end up trying to
construct something like: `{a * {c,+,d}<L2>,+,b * {c,+,d}<L2>}<L1>`, which is incorrect
because `AR2` is not available on entrance of `L1`.
Both situations "`L1` contains `L2`" and "`L1` preceeds sibling loop `L2`" can be handled
with one check: "header of `L1` dominates header of `L2`". This patch replaces the old
insufficient check with this one.
Differential Revision: https://reviews.llvm.org/D39453
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318819 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Analysis')
-rw-r--r-- | test/Analysis/ScalarEvolution/different-loops-recs.ll | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/test/Analysis/ScalarEvolution/different-loops-recs.ll b/test/Analysis/ScalarEvolution/different-loops-recs.ll index 6b88f09e936..8e207ed8147 100644 --- a/test/Analysis/ScalarEvolution/different-loops-recs.ll +++ b/test/Analysis/ScalarEvolution/different-loops-recs.ll @@ -510,3 +510,122 @@ exit: %tmp10 = add i32 %iv.1.2, 3 ret void } + +define i64 @test_09(i32 %param) { + +; CHECK-LABEL: Classifying expressions for: @test_09 +; CHECK: %iv1 = phi i64 [ %iv1.next, %guarded ], [ 0, %outer.loop ] +; CHECK-NEXT: --> {0,+,1}<nuw><nsw><%loop1> +; CHECK: %iv1.trunc = trunc i64 %iv1 to i32 +; CHECK-NEXT: --> {0,+,1}<%loop1> +; CHECK: %iv1.next = add nuw nsw i64 %iv1, 1 +; CHECK-NEXT: --> {1,+,1}<nuw><nsw><%loop1> +; CHECK: %iv2 = phi i32 [ %iv2.next, %loop2 ], [ %param, %loop2.preheader ] +; CHECK-NEXT: --> {%param,+,1}<%loop2> +; CHECK: %iv2.next = add i32 %iv2, 1 +; CHECK-NEXT: --> {(1 + %param),+,1}<%loop2> +; CHECK: %iv2.ext = sext i32 %iv2.next to i64 +; CHECK-NEXT: --> (sext i32 {(1 + %param),+,1}<%loop2> to i64) +; CHECK: %ret = mul i64 %iv1, %iv2.ext +; CHECK-NEXT: --> ((sext i32 {(1 + %param),+,1}<%loop2> to i64) * {0,+,1}<nuw><nsw><%loop1>) + +entry: + br label %outer.loop + +outer.loop: ; preds = %loop2.exit, %entry + br label %loop1 + +loop1: ; preds = %guarded, %outer.loop + %iv1 = phi i64 [ %iv1.next, %guarded ], [ 0, %outer.loop ] + %iv1.trunc = trunc i64 %iv1 to i32 + %cond1 = icmp ult i64 %iv1, 100 + br i1 %cond1, label %guarded, label %deopt + +guarded: ; preds = %loop1 + %iv1.next = add nuw nsw i64 %iv1, 1 + %tmp16 = icmp slt i32 %iv1.trunc, 2 + br i1 %tmp16, label %loop1, label %loop2.preheader + +deopt: ; preds = %loop1 + unreachable + +loop2.preheader: ; preds = %guarded + br label %loop2 + +loop2: ; preds = %loop2, %loop2.preheader + %iv2 = phi i32 [ %iv2.next, %loop2 ], [ %param, %loop2.preheader ] + %iv2.next = add i32 %iv2, 1 + %cond2 = icmp slt i32 %iv2, %iv1.trunc + br i1 %cond2, label %loop2, label %exit + +exit: ; preds = %loop2.exit + %iv2.ext = sext i32 %iv2.next to i64 + %ret = mul i64 %iv1, %iv2.ext + ret i64 %ret +} + +define i64 @test_10(i32 %param) { + +; CHECK-LABEL: Classifying expressions for: @test_10 +; CHECK: %uncle = phi i64 [ %uncle.outer.next, %uncle.loop.backedge ], [ 0, %outer.loop ] +; CHECK-NEXT: --> {0,+,1}<%uncle.loop> +; CHECK: %iv1 = phi i64 [ %iv1.next, %guarded ], [ 0, %uncle.loop ] +; CHECK-NEXT: --> {0,+,1}<nuw><nsw><%loop1> +; CHECK: %iv1.trunc = trunc i64 %iv1 to i32 +; CHECK-NEXT: --> {0,+,1}<%loop1> +; CHECK: %iv1.next = add nuw nsw i64 %iv1, 1 +; CHECK-NEXT: --> {1,+,1}<nuw><nsw><%loop1> +; CHECK: %uncle.outer.next = add i64 %uncle, 1 +; CHECK-NEXT: --> {1,+,1}<%uncle.loop> +; CHECK: %iv2 = phi i32 [ %iv2.next, %loop2 ], [ %param, %loop2.preheader ] +; CHECK-NEXT: --> {%param,+,1}<%loop2> +; CHECK: %iv2.next = add i32 %iv2, 1 +; CHECK-NEXT: --> {(1 + %param),+,1}<%loop2> +; CHECK: %iv2.ext = sext i32 %iv2.next to i64 +; CHECK-NEXT: --> (sext i32 {(1 + %param),+,1}<%loop2> to i64) +; CHECK: %ret = mul i64 %iv1, %iv2.ext +; CHECK-NEXT: --> ((sext i32 {(1 + %param),+,1}<%loop2> to i64) * {0,+,1}<nuw><nsw><%loop1>) + +entry: + br label %outer.loop + +outer.loop: ; preds = %entry + br label %uncle.loop + +uncle.loop: ; preds = %uncle.loop.backedge, %outer.loop + %uncle = phi i64 [ %uncle.outer.next, %uncle.loop.backedge ], [ 0, %outer.loop ] + br label %loop1 + +loop1: ; preds = %guarded, %uncle.loop + %iv1 = phi i64 [ %iv1.next, %guarded ], [ 0, %uncle.loop ] + %iv1.trunc = trunc i64 %iv1 to i32 + %cond1 = icmp ult i64 %iv1, 100 + br i1 %cond1, label %guarded, label %deopt + +guarded: ; preds = %loop1 + %iv1.next = add nuw nsw i64 %iv1, 1 + %tmp16 = icmp slt i32 %iv1.trunc, 2 + br i1 %tmp16, label %loop1, label %uncle.loop.backedge + +uncle.loop.backedge: ; preds = %guarded + %uncle.outer.next = add i64 %uncle, 1 + %cond.uncle = icmp ult i64 %uncle, 120 + br i1 %cond.uncle, label %loop2.preheader, label %uncle.loop + +deopt: ; preds = %loop1 + unreachable + +loop2.preheader: ; preds = %uncle.loop.backedge + br label %loop2 + +loop2: ; preds = %loop2, %loop2.preheader + %iv2 = phi i32 [ %iv2.next, %loop2 ], [ %param, %loop2.preheader ] + %iv2.next = add i32 %iv2, 1 + %cond2 = icmp slt i32 %iv2, %iv1.trunc + br i1 %cond2, label %loop2, label %exit + +exit: ; preds = %loop2 + %iv2.ext = sext i32 %iv2.next to i64 + %ret = mul i64 %iv1, %iv2.ext + ret i64 %ret +} |