8aacef6cae
We have found some corner cases connected to range intersection where IRCE makes a bad thing when the latch condition is unsigned. The fix for that will go as a follow up. This patch temporarily disables IRCE for unsigned latch conditions until the issue is fixed. The unsigned latch conditions were introduced to IRCE by rL310027. Differential Revision: https://reviews.llvm.org/D38529 llvm-svn: 314881
46 lines
1.7 KiB
LLVM
46 lines
1.7 KiB
LLVM
; RUN: opt -irce -S < %s 2>&1 | FileCheck %s
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; This test demonstrates a miscompile: the outer loop's IV iterates in range of
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; [2, 400) and the range check is done against value 331. Due to a bug in range
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; intersection IRCE manages to eliminate the range check without inserting a
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; postloop, which is incorrect. So far IRCE is prohibited for this case.
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define void @test_01() {
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; CHECK-LABEL: test_01
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; CHECK-NOT: br i1 true
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entry:
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br label %loop_header
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loop_header: ; preds = %loop_latch, %entry
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%iv = phi i32 [ 2, %entry ], [ %iv_next, %loop_latch ]
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%iv.prev = phi i32 [ 1, %entry ], [ %iv, %loop_latch ]
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%tmp2 = icmp sgt i32 %iv.prev, -1
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br i1 %tmp2, label %loop_header.split.us, label %exit
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loop_header.split.us: ; preds = %loop_header
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br label %inner_loop
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inner_loop: ; preds = %inner_loop, %loop_header.split.us
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%inner_iv = phi i32 [ 1, %loop_header.split.us ], [ %inner_iv_next, %inner_loop ]
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%inner_iv_next = add nuw nsw i32 %inner_iv, 1
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%inner_cond = icmp ult i32 %inner_iv_next, 31
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br i1 %inner_cond, label %inner_loop, label %range_check_block
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exit: ; preds = %loop_latch, %loop_header
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ret void
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range_check_block: ; preds = %inner_loop
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%range_check = icmp slt i32 %iv, 331
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br i1 %range_check, label %loop_latch, label %deopt
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loop_latch: ; preds = %range_check_block
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%iv_next = add i32 %iv, 1
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%loop_cond = icmp ult i32 %iv_next, 400
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br i1 %loop_cond, label %loop_header, label %exit
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deopt: ; preds = %range_check_block
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ret void
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}
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