9135137718
Diffing phi nodes was recently added to llvm-diff. However, there currently is a limitation where equivalent values cannot be detected as such, leading to false positive diff reports. If a phi node refers a value defined in a basic block dominated by the current basic block, for example a phi node in a loop header referring a value defined in the loop body, we cannot prove equivalence of the referred values, because the basic block containing the variable definition has not yet been processed. This commit adds a test case showing this behavior, serving as a precommit for an upcoming fix of the above. Differential Revision: https://reviews.llvm.org/D137262
50 lines
1.9 KiB
LLVM
50 lines
1.9 KiB
LLVM
; Diff file with itself
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; Due to a current limitation in llvm-diff, a diff is reported here.
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; RUN: not llvm-diff %s %s 2>&1 | FileCheck --check-prefix=SAME-FILE %s
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; Replace %newvar1 with %newvar2 in the phi node. This can only
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; be detected to be different once BB1 has been processed.
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; RUN: rm -f %t.ll
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; RUN: cat %s | sed -e 's/ %newvar1, %BB1 / %newvar2, %BB1 /' > %t.ll
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; RUN: not llvm-diff %s %t.ll 2>&1 | FileCheck --check-prefix DIFFERENT-VAR %s
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; SAME-FILE: in function func:
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; SAME-FILE-NEXT: in block %BB0:
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; SAME-FILE-NEXT: > %var = phi i32 [ 0, %ENTRY ], [ %newvar1, %BB1 ]
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; SAME-FILE-NEXT: > %cnd = icmp eq i32 %var, 0
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; SAME-FILE-NEXT: > br i1 %cnd, label %BB1, label %END
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; SAME-FILE-NEXT: < %var = phi i32 [ 0, %ENTRY ], [ %newvar1, %BB1 ]
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; SAME-FILE-NEXT: < %cnd = icmp eq i32 %var, 0
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; SAME-FILE-NEXT: < br i1 %cnd, label %BB1, label %END
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; DIFFERENT-VAR: in function func:
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; DIFFERENT-VAR-NEXT: in block %BB0:
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; DIFFERENT-VAR-NEXT: > %var = phi i32 [ 0, %ENTRY ], [ %newvar2, %BB1 ]
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; DIFFERENT-VAR-NEXT: > %cnd = icmp eq i32 %var, 0
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; DIFFERENT-VAR-NEXT: > br i1 %cnd, label %BB1, label %END
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; DIFFERENT-VAR-NEXT: < %var = phi i32 [ 0, %ENTRY ], [ %newvar1, %BB1 ]
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; DIFFERENT-VAR-NEXT: < %cnd = icmp eq i32 %var, 0
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; DIFFERENT-VAR-NEXT: < br i1 %cnd, label %BB1, label %END
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define i32 @func() {
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ENTRY:
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br label %BB0
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BB0:
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; When diffing this phi node, we need to detect whether
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; %newvar1 is equivalent, which is not known until BB1 has been processed.
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%var = phi i32 [ 0, %ENTRY ], [ %newvar1, %BB1 ]
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%cnd = icmp eq i32 %var, 0
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br i1 %cnd, label %BB1, label %END
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BB1:
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%newvar1 = add i32 %var, 1
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%newvar2 = add i32 %var, 2
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br label %BB0
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END:
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; Equivalence of the ret depends on equivalence of %var.
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; Even if %var differs, we do not report a diff here, because
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; this is an indirect diff caused by another diff.
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ret i32 %var
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}
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