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| author | Sanjoy Das <sanjoy@playingwithpointers.com> | 2015-09-25 19:59:57 +0000 |
|---|---|---|
| committer | Sanjoy Das <sanjoy@playingwithpointers.com> | 2015-09-25 19:59:57 +0000 |
| commit | d706fa8a0c281b22df73c08c08b61b3f0a460e30 (patch) | |
| tree | 2708e7ef36f0617d817e6948ffa814d3869b628b /llvm/test/Transforms/IndVarSimplify | |
| parent | df1635d3941600c1873d8eceb494edf7c32ee920 (diff) | |
| download | bcm5719-llvm-d706fa8a0c281b22df73c08c08b61b3f0a460e30.tar.gz bcm5719-llvm-d706fa8a0c281b22df73c08c08b61b3f0a460e30.zip | |
[SCEV] Teach isLoopBackedgeGuardedByCond to exploit trip counts.
Summary:
If the trip count of a specific backedge is `N`, then we know that
backedge is effectively guarded by the condition `{0,+,1} u< N`. This
change teaches SCEV to use this condition to prove things in
`isLoopBackedgeGuardedByCond`.
Depends on D12948
Depends on D12949
Reviewers: atrick, reames, majnemer, hfinkel
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D12950
llvm-svn: 248608
Diffstat (limited to 'llvm/test/Transforms/IndVarSimplify')
| -rw-r--r-- | llvm/test/Transforms/IndVarSimplify/eliminate-comparison.ll | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/llvm/test/Transforms/IndVarSimplify/eliminate-comparison.ll b/llvm/test/Transforms/IndVarSimplify/eliminate-comparison.ll index 261ba387028..957ebb7cfbf 100644 --- a/llvm/test/Transforms/IndVarSimplify/eliminate-comparison.ll +++ b/llvm/test/Transforms/IndVarSimplify/eliminate-comparison.ll @@ -356,5 +356,42 @@ define void @func_17(i32* %len.ptr) { ret void } -!0 = !{i32 0, i32 2147483647} +define i1 @func_18(i16* %tmp20, i32* %len.addr) { +; CHECK-LABEL: @func_18( +entry: + %len = load i32, i32* %len.addr, !range !0 + %tmp18 = icmp eq i32 %len, 0 + br i1 %tmp18, label %bb2, label %bb0.preheader + +bb0.preheader: + br label %bb0 + +bb0: +; CHECK: bb0: + %var_0.in = phi i32 [ %var_0, %bb1 ], [ %len, %bb0.preheader ] + %var_1 = phi i32 [ %tmp30, %bb1 ], [ 0, %bb0.preheader ] + %var_0 = add nsw i32 %var_0.in, -1 + %tmp23 = icmp ult i32 %var_1, %len +; CHECK: br i1 true, label %stay, label %bb2.loopexit + br i1 %tmp23, label %stay, label %bb2 + +stay: +; CHECK: stay: + %tmp25 = getelementptr inbounds i16, i16* %tmp20, i32 %var_1 + %tmp26 = load i16, i16* %tmp25 + %tmp29 = icmp eq i16 %tmp26, 0 + br i1 %tmp29, label %bb1, label %bb2 + +bb1: + %tmp30 = add i32 %var_1, 1 + %tmp31 = icmp eq i32 %var_0, 0 + br i1 %tmp31, label %bb3, label %bb0 + +bb2: + ret i1 false + +bb3: + ret i1 true +} +!0 = !{i32 0, i32 2147483647} |
