[PATCH] D50788: [LiveDebugVariables] Avoid faulty addDefsFromCopies in computeIntervals
Bjorn Pettersson via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Sat Aug 25 03:03:12 PDT 2018
This revision was automatically updated to reflect the committed changes.
Closed by commit rL340679: [LiveDebugVariables] Avoid faulty addDefsFromCopies in computeIntervals (authored by bjope, committed by ).
Repository:
rL LLVM
https://reviews.llvm.org/D50788
Files:
llvm/trunk/lib/CodeGen/LiveDebugVariables.cpp
llvm/trunk/test/CodeGen/X86/dbg-value-superreg-copy.mir
Index: llvm/trunk/test/CodeGen/X86/dbg-value-superreg-copy.mir
===================================================================
--- llvm/trunk/test/CodeGen/X86/dbg-value-superreg-copy.mir
+++ llvm/trunk/test/CodeGen/X86/dbg-value-superreg-copy.mir
@@ -0,0 +1,67 @@
+# RUN: llc -O1 -start-after simple-register-coalescing -o - %s | FileCheck %s
+
+--- |
+ target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+ target triple = "x86_64-pc-linux-gnu"
+
+ define i16 @foo(i8 %zzz) !dbg !4 {
+ entry:
+ ret i16 1
+ }
+
+ ; Function Attrs: nounwind readnone speculatable
+ declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+ !llvm.dbg.cu = !{!0}
+ !llvm.module.flags = !{!3}
+
+ !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !2)
+ !1 = !DIFile(filename: "test.c", directory: "")
+ !2 = !{}
+ !3 = !{i32 1, !"Debug Info Version", i32 3}
+ !4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 3, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0)
+ !5 = !DISubroutineType(types: !6)
+ !6 = !{null}
+ !7 = !DILocalVariable(name: "zzz", arg: 1, scope: !4, file: !1, line: 3, type: !8)
+ !8 = !DIBasicType(name: "char", size: 8, align: 8, encoding: DW_ATE_signed)
+ !9 = !DILocation(line: 0, scope: !4)
+ !10 = !DILocation(line: 4, column: 22, scope: !11)
+ !11 = distinct !DILexicalBlock(scope: !4, file: !1, line: 3, column: 19)
+
+...
+---
+name: foo
+tracksRegLiveness: true
+body: |
+ bb.0:
+ %0:gr16_abcd = MOV16ri 1
+
+ bb.1:
+ DBG_VALUE debug-use %0.sub_8bit_hi, debug-use $noreg, !7, !DIExpression(), debug-location !9
+ %1:gr16 = COPY %0
+ %2:gr16 = COPY %0
+
+ bb.2:
+ $ax = COPY %1
+ $dx = COPY %2
+ RETQ killed $ax, killed $dx
+...
+
+# This test case was created as a reproducer for a bug when we got incorrect
+# DBG_VALUE instructions after regalloc like this:
+#
+# movw $1, %cx
+# #DEBUG_VALUE: foo:zzz <- $ch
+# movl %ecx, %eax
+# #DEBUG_VALUE: foo:zzz <- $ax
+#
+# The above is incorrect since the DBG_VALUE in the input is refering to the
+# hi subreg, so after the COPY/movl the value is in $ah and not $ax (nor $al).
+#
+# We currently only get one DEBUG_VALUE here. In the future we could allow a
+# second DEBUG_VALUE, as long as it is mapped to the hi subreg of the movl
+# dst.
+#
+# CHECK-NOT: #DEBUG_VALUE:
+# CHECK: #DEBUG_VALUE: foo:zzz <- ${{[abcd]+}}h
+# CHECK-NOT: #DEBUG_VALUE:
Index: llvm/trunk/lib/CodeGen/LiveDebugVariables.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/LiveDebugVariables.cpp
+++ llvm/trunk/lib/CodeGen/LiveDebugVariables.cpp
@@ -752,7 +752,15 @@
}
SmallVector<SlotIndex, 16> Kills;
extendDef(Idx, Loc, LI, VNI, &Kills, LIS);
- if (LI)
+ // FIXME: Handle sub-registers in addDefsFromCopies. The problem is that
+ // if the original location for example is %vreg0:sub_hi, and we find a
+ // full register copy in addDefsFromCopies (at the moment it only handles
+ // full register copies), then we must add the sub1 sub-register index to
+ // the new location. However, that is only possible if the new virtual
+ // register is of the same regclass (or if there is an equivalent
+ // sub-register in that regclass). For now, simply skip handling copies if
+ // a sub-register is involved.
+ if (LI && !LocMO.getSubReg())
addDefsFromCopies(LI, Loc.locNo(), Loc.wasIndirect(), Kills, Defs, MRI,
LIS);
continue;
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