[PATCH] D62555: prevent tail duplication for INLINEASM_BR

[Nick Desaulniers via Phabricator via llvm-commits]

nickdesaulniers created this revision.
nickdesaulniers added reviewers: craig.topper, peter.smith.
Herald added subscribers: llvm-commits, hiraditya, javed.absar.
Herald added a project: LLVM.

Otherwise we leave behind bad references to non-existent basic blocks
that result in missing symbols at link time for release builds, or
failed assertions later in If Converter pass.

pr/42012
Link: https://github.com/ClangBuiltLinux/linux/issues/494


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D62555

Files:
  llvm/lib/CodeGen/TailDuplicator.cpp
  llvm/test/CodeGen/ARM/taildup.ll


Index: llvm/test/CodeGen/ARM/taildup.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/ARM/taildup.ll
@@ -0,0 +1,55 @@
+; RUN: llc -mtriple=arm-linux-gnueabi -print-machineinstrs=tailduplication %s \
+; RUN:   -o /dev/null 2>&1 | FileCheck %s
+
+; Check that INLINEASM_BR did not get duplicated into the previously duplicated
+; blocks. Test case is a c-reduced then bugpointed sound/soc/ti/davinci-i2s.c
+; from the Linux kernel.
+
+; CHECK: bb.2.if.else:
+; CHECK: INLINEASM &"str $1, $0" [sideeffect] [mayload] [attdialect], $0:[mem:Q], killed renamable $r0, $1:[reguse:GPR], killed renamable $r1, !7
+; CHECK: bb.3.if.end:
+; CHECK: INLINEASM_BR &"" [sideeffect] [attdialect], $0:[imm], blockaddress(@f, %ir-block.g), !8
+
+ at a = external dso_local local_unnamed_addr global i32*, align 4
+ at c = external dso_local local_unnamed_addr global i32, align 4
+
+define dso_local i32 @f() #0 {
+entry:
+  %0 = load i32, i32* @c, align 4, !tbaa !1
+  %tobool = icmp eq i32 %0, 0
+  %1 = load i32*, i32** @a, align 4, !tbaa !5
+  br i1 %tobool, label %if.else, label %if.then
+
+if.then:                                          ; preds = %entry
+  tail call void asm sideeffect "str $1, $0", "*Qo,r"(i32* %1, i32 1) #1, !srcloc !7
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  tail call void asm sideeffect "str $1, $0", "*Qo,r"(i32* %1, i32 0) #1, !srcloc !7
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  callbr void asm sideeffect "", "X"(i8* blockaddress(@f, %g)) #1
+          to label %asm.fallthrough [label %g], !srcloc !8
+
+asm.fallthrough:                                  ; preds = %if.end
+  unreachable
+
+g:                                                ; preds = %if.end
+  ret i32 undef
+}
+
+attributes #0 = { "use-soft-float"="false" }
+attributes #1 = { nounwind }
+
+!llvm.ident = !{!0}
+
+!0 = !{!"clang version 9.0.0 (https://github.com/llvm/llvm-project.git 566858581206d1d7c0fd61886b11292c8ddce80b)"}
+!1 = !{!2, !2, i64 0}
+!2 = !{!"int", !3, i64 0}
+!3 = !{!"omnipotent char", !4, i64 0}
+!4 = !{!"Simple C/C++ TBAA"}
+!5 = !{!6, !6, i64 0}
+!6 = !{!"any pointer", !3, i64 0}
+!7 = !{i32 27}
+!8 = !{i32 118}
Index: llvm/lib/CodeGen/TailDuplicator.cpp
===================================================================
--- llvm/lib/CodeGen/TailDuplicator.cpp
+++ llvm/lib/CodeGen/TailDuplicator.cpp
@@ -781,6 +781,9 @@
     return false;
   if (!PredCond.empty())
     return false;
+  for (MachineInstr &I : *TailBB)
+    if (I.getOpcode() == TargetOpcode::INLINEASM_BR)
+      return false;
   return true;
 }
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D62555.201780.patch
Type: text/x-patch
Size: 2700 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20190528/d5b51147/attachment.bin>