1 files changed, 51 insertions, 54 deletions
diff --git a/llvm/test/CodeGen/PowerPC/expand-contiguous-isel.ll b/llvm/test/CodeGen/PowerPC/expand-contiguous-isel.ll
index a8ed09c1897..86caedcc09f 100644
--- a/llvm/test/CodeGen/PowerPC/expand-contiguous-isel.ll
+++ b/llvm/test/CodeGen/PowerPC/expand-contiguous-isel.ll
@@ -1,55 +1,66 @@
 target datalayout = "e-m:e-i64:64-n32:64"
 target triple = "powerpc64le-unknown-linux-gnu"
 ; This file mainly tests that one of the ISEL instruction in the group uses the same register for operand RT, RA, RB
+; This redudant ISEL is introduced during simple register coalescing stage.
+
+; Simple register coalescing first create the foldable ISEL instruction as we have seen in expand-foldable-isel.ll:
+; %vreg85<def> = ISEL8 %vreg83, %vreg83, %vreg33:sub_eq
+
+; Later the register coalescer figures out it could further coalesce %vreg85 with %vreg83:
+; merge %vreg85:1@2288r into %vreg83:5@400B --> @400B
+; erased:	2288r	%vreg85<def> = COPY %vreg83
+
+; After that we have:
+; updated: 1504B	%vreg83<def> = ISEL8 %vreg83, %vreg83, %vreg33:sub_eq
+
 ; RUN: llc -verify-machineinstrs -O2 -ppc-asm-full-reg-names -mcpu=pwr7 -ppc-gen-isel=true < %s | FileCheck %s --check-prefix=CHECK-GEN-ISEL-TRUE
 ; RUN: llc -verify-machineinstrs -O2 -ppc-asm-full-reg-names -mcpu=pwr7 -ppc-gen-isel=false < %s | FileCheck %s --implicit-check-not isel
-; Function Attrs: norecurse nounwind readnone
+
 @.str = private unnamed_addr constant [3 x i8] c"]]\00", align 1
 @.str.1 = private unnamed_addr constant [35 x i8] c"Index < Length && \22Invalid index!\22\00", align 1
 @.str.2 = private unnamed_addr constant [50 x i8] c"/home/jtony/src/llvm/include/llvm/ADT/StringRef.h\00", align 1
 @__PRETTY_FUNCTION__._ZNK4llvm9StringRefixEm = private unnamed_addr constant [47 x i8] c"char llvm::StringRef::operator[](size_t) const\00", align 1
 @.str.3 = private unnamed_addr constant [95 x i8] c"(data || length == 0) && \22StringRef cannot be built from a NULL argument with non-null length\22\00", align 1
 @__PRETTY_FUNCTION__._ZN4llvm9StringRefC2EPKcm = private unnamed_addr constant [49 x i8] c"llvm::StringRef::StringRef(const char *, size_t)\00", align 1
-; Function Attrs: nounwind
-define i64 @_Z3fn1N4llvm9StringRefE([2 x i64] %Str.coerce) local_unnamed_addr #0 {
+define i64 @_Z3fn1N4llvm9StringRefE([2 x i64] %Str.coerce) {
 entry:
   %Str.coerce.fca.0.extract = extractvalue [2 x i64] %Str.coerce, 0
   %Str.coerce.fca.1.extract = extractvalue [2 x i64] %Str.coerce, 1
   br label %while.cond.outer
-while.cond.outer:                                 ; preds = %_ZNK4llvm9StringRef6substrEmm.exit, %entry
+while.cond.outer:
   %Str.sroa.0.0.ph = phi i64 [ %8, %_ZNK4llvm9StringRef6substrEmm.exit ], [ %Str.coerce.fca.0.extract, %entry ]
   %.sink.ph = phi i64 [ %sub.i, %_ZNK4llvm9StringRef6substrEmm.exit ], [ %Str.coerce.fca.1.extract, %entry ]
   %BracketDepth.0.ph = phi i64 [ %BracketDepth.1, %_ZNK4llvm9StringRef6substrEmm.exit ], [ undef, %entry ]
   %cmp65 = icmp eq i64 %BracketDepth.0.ph, 0
   br i1 %cmp65, label %while.cond.us.preheader, label %while.cond.preheader
-while.cond.us.preheader:                          ; preds = %while.cond.outer
+while.cond.us.preheader:
   br label %while.cond.us
-while.cond.preheader:                             ; preds = %while.cond.outer
+while.cond.preheader:
   %cmp.i34129 = icmp eq i64 %.sink.ph, 0
   br i1 %cmp.i34129, label %cond.false.i.loopexit135, label %_ZNK4llvm9StringRefixEm.exit.preheader
-_ZNK4llvm9StringRefixEm.exit.preheader:           ; preds = %while.cond.preheader
+_ZNK4llvm9StringRefixEm.exit.preheader:
   br label %_ZNK4llvm9StringRefixEm.exit
-while.cond.us:                                    ; preds = %while.cond.us.preheader, %_ZNK4llvm9StringRef6substrEmm.exit50.us
+while.cond.us:
   %Str.sroa.0.0.us = phi i64 [ %3, %_ZNK4llvm9StringRef6substrEmm.exit50.us ], [ %Str.sroa.0.0.ph, %while.cond.us.preheader ]
   %.sink.us = phi i64 [ %sub.i41.us, %_ZNK4llvm9StringRef6substrEmm.exit50.us ], [ %.sink.ph, %while.cond.us.preheader ]
   %cmp.i30.us = icmp ult i64 %.sink.us, 2
   br i1 %cmp.i30.us, label %if.end.us, label %if.end.i.i.us
-if.end.i.i.us:                                    ; preds = %while.cond.us
+if.end.i.i.us:
   %0 = inttoptr i64 %Str.sroa.0.0.us to i8*
-  %call.i.i.us = tail call signext i32 @memcmp(i8* %0, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), i64 2) #3
+  %call.i.i.us = tail call signext i32 @memcmp(i8* %0, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), i64 2)
   %phitmp.i.us = icmp eq i32 %call.i.i.us, 0
   br i1 %phitmp.i.us, label %if.then, label %_ZNK4llvm9StringRefixEm.exit.us
-if.end.us:                                        ; preds = %while.cond.us
+if.end.us:
   %cmp.i34.us = icmp eq i64 %.sink.us, 0
   br i1 %cmp.i34.us, label %cond.false.i.loopexit, label %_ZNK4llvm9StringRefixEm.exit.us
-_ZNK4llvm9StringRefixEm.exit.us:                  ; preds = %if.end.i.i.us, %if.end.us
+_ZNK4llvm9StringRefixEm.exit.us:
   %1 = inttoptr i64 %Str.sroa.0.0.us to i8*
-  %2 = load i8, i8* %1, align 1, !tbaa !2
+  %2 = load i8, i8* %1, align 1
   switch i8 %2, label %_ZNK4llvm9StringRef6substrEmm.exit.loopexit [
     i8 92, label %if.then4.us
     i8 93, label %if.then9
   ]
-if.then4.us:                                      ; preds = %_ZNK4llvm9StringRefixEm.exit.us
+if.then4.us:
   %.sroa.speculated12.i38.us = select i1 %cmp.i30.us, i64 %.sink.us, i64 2
   %add.ptr.i40.us = getelementptr inbounds i8, i8* %1, i64 %.sroa.speculated12.i38.us
   %sub.i41.us = sub i64 %.sink.us, %.sroa.speculated12.i38.us
@@ -57,30 +68,30 @@ if.then4.us:                                      ; preds = %_ZNK4llvm9StringRef
   %cmp.i4.i45.us = icmp eq i64 %sub.i41.us, 0
   %or.cond.i.i46.us = or i1 %tobool.i.i44.us, %cmp.i4.i45.us
   br i1 %or.cond.i.i46.us, label %_ZNK4llvm9StringRef6substrEmm.exit50.us, label %cond.false.i.i47.loopexit
-_ZNK4llvm9StringRef6substrEmm.exit50.us:          ; preds = %if.then4.us
+_ZNK4llvm9StringRef6substrEmm.exit50.us:
   %3 = ptrtoint i8* %add.ptr.i40.us to i64
   br label %while.cond.us
-if.then:                                          ; preds = %if.end.i.i.us
+if.then:
   ret i64 undef
-cond.false.i.loopexit:                            ; preds = %if.end.us
+cond.false.i.loopexit:
   br label %cond.false.i
-cond.false.i.loopexit134:                         ; preds = %_ZNK4llvm9StringRef6substrEmm.exit50
+cond.false.i.loopexit134:
   br label %cond.false.i
-cond.false.i.loopexit135:                         ; preds = %while.cond.preheader
+cond.false.i.loopexit135:
   br label %cond.false.i
-cond.false.i:                                     ; preds = %cond.false.i.loopexit135, %cond.false.i.loopexit134, %cond.false.i.loopexit
-  tail call void @__assert_fail(i8* getelementptr inbounds ([35 x i8], [35 x i8]* @.str.1, i64 0, i64 0), i8* getelementptr inbounds ([50 x i8], [50 x i8]* @.str.2, i64 0, i64 0), i32 zeroext 225, i8* getelementptr inbounds ([47 x i8], [47 x i8]* @__PRETTY_FUNCTION__._ZNK4llvm9StringRefixEm, i64 0, i64 0)) #4
+cond.false.i:
+  tail call void @__assert_fail(i8* getelementptr inbounds ([35 x i8], [35 x i8]* @.str.1, i64 0, i64 0), i8* getelementptr inbounds ([50 x i8], [50 x i8]* @.str.2, i64 0, i64 0), i32 zeroext 225, i8* getelementptr inbounds ([47 x i8], [47 x i8]* @__PRETTY_FUNCTION__._ZNK4llvm9StringRefixEm, i64 0, i64 0))
   unreachable
-_ZNK4llvm9StringRefixEm.exit:                     ; preds = %_ZNK4llvm9StringRefixEm.exit.preheader, %_ZNK4llvm9StringRef6substrEmm.exit50
+_ZNK4llvm9StringRefixEm.exit:
   %.sink131 = phi i64 [ %sub.i41, %_ZNK4llvm9StringRef6substrEmm.exit50 ], [ %.sink.ph, %_ZNK4llvm9StringRefixEm.exit.preheader ]
   %Str.sroa.0.0130 = phi i64 [ %6, %_ZNK4llvm9StringRef6substrEmm.exit50 ], [ %Str.sroa.0.0.ph, %_ZNK4llvm9StringRefixEm.exit.preheader ]
   %4 = inttoptr i64 %Str.sroa.0.0130 to i8*
-  %5 = load i8, i8* %4, align 1, !tbaa !2
+  %5 = load i8, i8* %4, align 1
   switch i8 %5, label %_ZNK4llvm9StringRef6substrEmm.exit.loopexit132 [
     i8 92, label %if.then4
     i8 93, label %if.end10
   ]
-if.then4:                                         ; preds = %_ZNK4llvm9StringRefixEm.exit
+if.then4:
   %cmp.i.i37 = icmp ult i64 %.sink131, 2
   %.sroa.speculated12.i38 = select i1 %cmp.i.i37, i64 %.sink131, i64 2
   %add.ptr.i40 = getelementptr inbounds i8, i8* %4, i64 %.sroa.speculated12.i38
@@ -89,28 +100,28 @@ if.then4:                                         ; preds = %_ZNK4llvm9StringRef
   %cmp.i4.i45 = icmp eq i64 %sub.i41, 0
   %or.cond.i.i46 = or i1 %tobool.i.i44, %cmp.i4.i45
   br i1 %or.cond.i.i46, label %_ZNK4llvm9StringRef6substrEmm.exit50, label %cond.false.i.i47.loopexit133
-cond.false.i.i47.loopexit:                        ; preds = %if.then4.us
+cond.false.i.i47.loopexit:
   br label %cond.false.i.i47
-cond.false.i.i47.loopexit133:                     ; preds = %if.then4
+cond.false.i.i47.loopexit133:
   br label %cond.false.i.i47
-cond.false.i.i47:                                 ; preds = %cond.false.i.i47.loopexit133, %cond.false.i.i47.loopexit
-  tail call void @__assert_fail(i8* getelementptr inbounds ([95 x i8], [95 x i8]* @.str.3, i64 0, i64 0), i8* getelementptr inbounds ([50 x i8], [50 x i8]* @.str.2, i64 0, i64 0), i32 zeroext 90, i8* getelementptr inbounds ([49 x i8], [49 x i8]* @__PRETTY_FUNCTION__._ZN4llvm9StringRefC2EPKcm, i64 0, i64 0)) #4
+cond.false.i.i47:
+  tail call void @__assert_fail(i8* getelementptr inbounds ([95 x i8], [95 x i8]* @.str.3, i64 0, i64 0), i8* getelementptr inbounds ([50 x i8], [50 x i8]* @.str.2, i64 0, i64 0), i32 zeroext 90, i8* getelementptr inbounds ([49 x i8], [49 x i8]* @__PRETTY_FUNCTION__._ZN4llvm9StringRefC2EPKcm, i64 0, i64 0))
   unreachable
-_ZNK4llvm9StringRef6substrEmm.exit50:             ; preds = %if.then4
+_ZNK4llvm9StringRef6substrEmm.exit50:
   %6 = ptrtoint i8* %add.ptr.i40 to i64
   %cmp.i34 = icmp eq i64 %sub.i41, 0
   br i1 %cmp.i34, label %cond.false.i.loopexit134, label %_ZNK4llvm9StringRefixEm.exit
-if.then9:                                         ; preds = %_ZNK4llvm9StringRefixEm.exit.us
-  tail call void @exit(i32 signext 1) #4
+if.then9:
+  tail call void @exit(i32 signext 1)
   unreachable
-if.end10:                                         ; preds = %_ZNK4llvm9StringRefixEm.exit
+if.end10:
   %dec = add i64 %BracketDepth.0.ph, -1
   br label %_ZNK4llvm9StringRef6substrEmm.exit
-_ZNK4llvm9StringRef6substrEmm.exit.loopexit:      ; preds = %_ZNK4llvm9StringRefixEm.exit.us
+_ZNK4llvm9StringRef6substrEmm.exit.loopexit:
   br label %_ZNK4llvm9StringRef6substrEmm.exit
-_ZNK4llvm9StringRef6substrEmm.exit.loopexit132:   ; preds = %_ZNK4llvm9StringRefixEm.exit
+_ZNK4llvm9StringRef6substrEmm.exit.loopexit132:
   br label %_ZNK4llvm9StringRef6substrEmm.exit
-_ZNK4llvm9StringRef6substrEmm.exit:               ; preds = %_ZNK4llvm9StringRef6substrEmm.exit.loopexit132, %_ZNK4llvm9StringRef6substrEmm.exit.loopexit, %if.end10
+_ZNK4llvm9StringRef6substrEmm.exit:
   %.sink76 = phi i64 [ %.sink131, %if.end10 ], [ %.sink.us, %_ZNK4llvm9StringRef6substrEmm.exit.loopexit ], [ %.sink131, %_ZNK4llvm9StringRef6substrEmm.exit.loopexit132 ]
   %7 = phi i8* [ %4, %if.end10 ], [ %1, %_ZNK4llvm9StringRef6substrEmm.exit.loopexit ], [ %4, %_ZNK4llvm9StringRef6substrEmm.exit.loopexit132 ]
   %BracketDepth.1 = phi i64 [ %dec, %if.end10 ], [ 0, %_ZNK4llvm9StringRef6substrEmm.exit.loopexit ], [ %BracketDepth.0.ph, %_ZNK4llvm9StringRef6substrEmm.exit.loopexit132 ]
@@ -120,7 +131,8 @@ _ZNK4llvm9StringRef6substrEmm.exit:               ; preds = %_ZNK4llvm9StringRef
   br label %while.cond.outer
 
 ; CHECK-LABEL: @_Z3fn1N4llvm9StringRefE
-; CHECK-GEN-ISEL-TRUE: isel [[SAME:r[0-9]+]], [[SAME]], [[SAME]]
+; Unecessary ISEL (all the registers are the same) is always removed
+; CHECK-GEN-ISEL-TRUE-NOT: isel [[SAME:r[0-9]+]], [[SAME]], [[SAME]]
 ; CHECK-GEN-ISEL-TRUE: isel [[SAME:r[0-9]+]], {{r[0-9]+}}, [[SAME]]
 ; CHECK: bc 12, eq, [[TRUE:.LBB[0-9]+]]
 ; CHECK-NEXT: b [[SUCCESSOR:.LBB[0-9]+]]
@@ -131,21 +143,6 @@ _ZNK4llvm9StringRef6substrEmm.exit:               ; preds = %_ZNK4llvm9StringRef
 
 
 
-; Function Attrs: noreturn nounwind
-declare void @exit(i32 signext) local_unnamed_addr #1
-; Function Attrs: nounwind readonly
-declare signext i32 @memcmp(i8* nocapture, i8* nocapture, i64) local_unnamed_addr #2
-; Function Attrs: noreturn nounwind
-declare void @__assert_fail(i8*, i8*, i32 zeroext, i8*) local_unnamed_addr #1
-attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="ppc64le" "target-features"="+altivec,+bpermd,+crypto,+direct-move,+extdiv,+power8-vector,+vsx,-power9-vector,-qpx" "unsafe-fp-math"="false" "use-soft-float"="false" }
-attributes #1 = { noreturn nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="ppc64le" "target-features"="+altivec,+bpermd,+crypto,+direct-move,+extdiv,+power8-vector,+vsx,-power9-vector,-qpx" "unsafe-fp-math"="false" "use-soft-float"="false" }
-attributes #2 = { nounwind readonly "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="ppc64le" "target-features"="+altivec,+bpermd,+crypto,+direct-move,+extdiv,+power8-vector,+vsx,-power9-vector,-qpx" "unsafe-fp-math"="false" "use-soft-float"="false" }
-attributes #3 = { nounwind readonly }
-attributes #4 = { noreturn nounwind }
-!llvm.module.flags = !{!0}
-!llvm.ident = !{!1}
-!0 = !{i32 1, !"PIC Level", i32 2}
-!1 = !{!"clang version 4.0.0 (trunk 286863) (llvm/trunk 286967)"}
-!2 = !{!3, !3, i64 0}
-!3 = !{!"omnipotent char", !4, i64 0}
-!4 = !{!"Simple C++ TBAA"}
+declare void @exit(i32 signext)
+declare signext i32 @memcmp(i8* nocapture, i8* nocapture, i64)
+declare void @__assert_fail(i8*, i8*, i32 zeroext, i8*)