Keep track of phi join registers explicitly in LiveVariables.

Previously, LiveIntervalAnalysis would infer phi joins by looking for multiply
defined registers. That doesn't work if the phi join is implicitly defined in
all but one of the predecessors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96994 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 146 insertions, 0 deletions

diff --git a/test/CodeGen/X86/2010-02-23-SingleDefPhiJoin.ll b/test/CodeGen/X86/2010-02-23-SingleDefPhiJoin.ll
new file mode 100644
index 0000000000..aeed401461
--- /dev/null
+++ b/test/CodeGen/X86/2010-02-23-SingleDefPhiJoin.ll
@@ -0,0 +1,146 @@
+; RUN: llc < %s
+; PR6363
+;
+; This test case creates a phi join register with a single definition. The other
+; predecessor blocks are implicit-def.
+;
+; If LiveIntervalAnalysis fails to recognize this as a phi join, the coalescer
+; will detect an infinity valno loop.
+;
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @decode(i8* nocapture %input, i32 %offset, i8* nocapture %output) nounwind {
+entry:
+  br i1 undef, label %meshBB86, label %meshBB102
+
+bb:                                               ; preds = %meshBB106, %meshBB102
+  br i1 false, label %bb9, label %meshBB90
+
+bb.nph:                                           ; preds = %meshBB90
+  br label %meshBB114
+
+bb.nph.fragment:                                  ; preds = %meshBB114
+  br label %meshBB118
+
+bb1.fragment:                                     ; preds = %meshBB118
+  br i1 false, label %bb2, label %bb3
+
+bb2:                                              ; preds = %bb1.fragment
+  br label %meshBB74
+
+bb2.fragment15:                                   ; preds = %meshBB74
+  br label %meshBB98
+
+bb3:                                              ; preds = %bb1.fragment
+  br i1 undef, label %meshBB, label %meshBB102
+
+bb4:                                              ; preds = %meshBB
+  br label %meshBB118
+
+bb4.fragment:                                     ; preds = %meshBB118
+  br label %meshBB82
+
+bb5:                                              ; preds = %meshBB102, %meshBB82
+  br i1 false, label %bb6, label %bb7
+
+bb6:                                              ; preds = %bb5
+  br label %bb7
+
+bb7:                                              ; preds = %meshBB98, %bb6, %bb5
+  br label %meshBB114
+
+bb7.fragment:                                     ; preds = %meshBB114
+  br i1 undef, label %meshBB74, label %bb9
+
+bb9:                                              ; preds = %bb7.fragment, %bb
+  br label %bb1.i23
+
+bb1.i23:                                          ; preds = %meshBB110, %bb9
+  br i1 undef, label %meshBB106, label %meshBB110
+
+skip_to_newline.exit26:                           ; preds = %meshBB106
+  br label %meshBB86
+
+skip_to_newline.exit26.fragment:                  ; preds = %meshBB86
+  br i1 false, label %meshBB90, label %meshBB106
+
+bb11.fragment:                                    ; preds = %meshBB90, %meshBB86
+  br label %meshBB122
+
+bb1.i:                                            ; preds = %meshBB122, %meshBB
+  %ooffset.2.lcssa.phi.SV.phi203 = phi i32 [ 0, %meshBB122 ], [ %ooffset.2.lcssa.phi.SV.phi233, %meshBB ] ; <i32> [#uses=1]
+  br label %meshBB98
+
+bb1.i.fragment:                                   ; preds = %meshBB98
+  br i1 undef, label %meshBB78, label %meshBB
+
+skip_to_newline.exit:                             ; preds = %meshBB78
+  br i1 undef, label %bb12, label %meshBB110
+
+bb12:                                             ; preds = %skip_to_newline.exit
+  br label %meshBB94
+
+bb12.fragment:                                    ; preds = %meshBB94
+  br i1 false, label %bb13, label %meshBB78
+
+bb13:                                             ; preds = %bb12.fragment
+  br label %meshBB82
+
+bb13.fragment:                                    ; preds = %meshBB82
+  br i1 undef, label %meshBB94, label %meshBB122
+
+bb14:                                             ; preds = %meshBB94
+  ret i32 %ooffset.2.lcssa.phi.SV.phi250
+
+bb15:                                             ; preds = %meshBB122, %meshBB110, %meshBB78
+  unreachable
+
+meshBB:                                           ; preds = %bb1.i.fragment, %bb3
+  %ooffset.2.lcssa.phi.SV.phi233 = phi i32 [ undef, %bb3 ], [ %ooffset.2.lcssa.phi.SV.phi209, %bb1.i.fragment ] ; <i32> [#uses=1]
+  br i1 undef, label %bb1.i, label %bb4
+
+meshBB74:                                         ; preds = %bb7.fragment, %bb2
+  br i1 false, label %meshBB118, label %bb2.fragment15
+
+meshBB78:                                         ; preds = %bb12.fragment, %bb1.i.fragment
+  %ooffset.2.lcssa.phi.SV.phi239 = phi i32 [ %ooffset.2.lcssa.phi.SV.phi209, %bb1.i.fragment ], [ %ooffset.2.lcssa.phi.SV.phi250, %bb12.fragment ] ; <i32> [#uses=1]
+  br i1 false, label %bb15, label %skip_to_newline.exit
+
+meshBB82:                                         ; preds = %bb13, %bb4.fragment
+  br i1 false, label %bb5, label %bb13.fragment
+
+meshBB86:                                         ; preds = %skip_to_newline.exit26, %entry
+  br i1 undef, label %skip_to_newline.exit26.fragment, label %bb11.fragment
+
+meshBB90:                                         ; preds = %skip_to_newline.exit26.fragment, %bb
+  br i1 false, label %bb11.fragment, label %bb.nph
+
+meshBB94:                                         ; preds = %bb13.fragment, %bb12
+  %ooffset.2.lcssa.phi.SV.phi250 = phi i32 [ 0, %bb13.fragment ], [ %ooffset.2.lcssa.phi.SV.phi239, %bb12 ] ; <i32> [#uses=2]
+  br i1 false, label %bb12.fragment, label %bb14
+
+meshBB98:                                         ; preds = %bb1.i, %bb2.fragment15
+  %ooffset.2.lcssa.phi.SV.phi209 = phi i32 [ undef, %bb2.fragment15 ], [ %ooffset.2.lcssa.phi.SV.phi203, %bb1.i ] ; <i32> [#uses=2]
+  br i1 undef, label %bb1.i.fragment, label %bb7
+
+meshBB102:                                        ; preds = %bb3, %entry
+  br i1 undef, label %bb5, label %bb
+
+meshBB106:                                        ; preds = %skip_to_newline.exit26.fragment, %bb1.i23
+  br i1 undef, label %bb, label %skip_to_newline.exit26
+
+meshBB110:                                        ; preds = %skip_to_newline.exit, %bb1.i23
+  br i1 false, label %bb15, label %bb1.i23
+
+meshBB114:                                        ; preds = %bb7, %bb.nph
+  %meshStackVariable115.phi = phi i32 [ 19, %bb7 ], [ 8, %bb.nph ] ; <i32> [#uses=0]
+  br i1 undef, label %bb.nph.fragment, label %bb7.fragment
+
+meshBB118:                                        ; preds = %meshBB74, %bb4, %bb.nph.fragment
+  %meshCmp121 = icmp eq i32 undef, 10             ; <i1> [#uses=1]
+  br i1 %meshCmp121, label %bb4.fragment, label %bb1.fragment
+
+meshBB122:                                        ; preds = %bb13.fragment, %bb11.fragment
+  br i1 false, label %bb1.i, label %bb15
+}