Teach basic AA about PHI nodes. If all operands of a phi NoAlias another value than it's safe to declare the PHI NoAlias the value. Ditto for MustAlias.

llvm-svn: 84038

1 files changed, 86 insertions, 0 deletions

diff --git a/llvm/test/Analysis/BasicAA/phi-aa.ll b/llvm/test/Analysis/BasicAA/phi-aa.ll
new file mode 100644
index 00000000000..a3e89e963c0
--- /dev/null
+++ b/llvm/test/Analysis/BasicAA/phi-aa.ll
@@ -0,0 +1,86 @@
+; RUN: opt < %s -basicaa -licm -S | FileCheck %s
+; rdar://7282591
+
+%struct.CFRuntimeBase = type { i32, [4 x i8] }
+%struct.XXXAffineTransform = type { float, float, float, float, float, float }
+%struct.XXXContext = type { %struct.CFRuntimeBase, i32, i32, i32, i8*, %struct.XXXContextDelegate*, void (%struct.XXXContext*)*, void (%struct.XXXContext*)*, %struct.XXXImage* (%struct.XXXContext*, %struct.XXXRect*, %struct.XXXImage*, i8*)*, i8*, %struct.__CFDictionary*, i32, %struct.XXXGState*, %struct.XXXGStack*, %struct.XXXRenderingState*, %struct.XXXAffineTransform, %struct.XXXPath*, %struct.__CFDictionary*, %struct.XXXPixelAccess* }
+%struct.XXXContextDelegate = type opaque
+%struct.XXXGStack = type opaque
+%struct.XXXGState = type opaque
+%struct.XXXImage = type opaque
+%struct.XXXPath = type opaque
+%struct.XXXPixelAccess = type opaque
+%struct.XXXPoint = type { float, float }
+%struct.XXXRect = type { %struct.XXXPoint, %struct.XXXPoint }
+%struct.XXXRenderingState = type opaque
+%struct.__CFDictionary = type opaque
+
+define void @t(%struct.XXXContext* %context, i16* %glyphs, %struct.XXXPoint* %advances, i32 %count) nounwind optsize ssp {
+; CHECK: @t
+; CHECK: bb21.preheader:
+; CHECK: %tmp28 = getelementptr
+; CHECK: %tmp28.promoted = load
+entry:
+  br i1 undef, label %bb1, label %bb
+
+bb:                                               ; preds = %entry
+  br i1 undef, label %bb2, label %bb1
+
+bb1:                                              ; preds = %bb, %entry
+  ret void
+
+bb2:                                              ; preds = %bb
+  br i1 undef, label %bb35, label %bb7
+
+bb7:                                              ; preds = %bb2
+  br i1 undef, label %bb35, label %bb10
+
+bb10:                                             ; preds = %bb7
+  %tmp18 = alloca i8, i32 undef, align 1          ; <i8*> [#uses=1]
+  br i1 undef, label %bb35, label %bb15
+
+bb15:                                             ; preds = %bb10
+  br i1 undef, label %bb17, label %bb16
+
+bb16:                                             ; preds = %bb15
+  %tmp21 = bitcast i8* %tmp18 to %struct.XXXPoint* ; <%struct.XXXPoint*> [#uses=1]
+  br label %bb18
+
+bb17:                                             ; preds = %bb15
+  %tmp22 = malloc %struct.XXXPoint, i32 %count     ; <%struct.XXXPoint*> [#uses=1]
+  br label %bb18
+
+bb18:                                             ; preds = %bb17, %bb16
+  %positions.0 = phi %struct.XXXPoint* [ %tmp21, %bb16 ], [ %tmp22, %bb17 ] ; <%struct.XXXPoint*> [#uses=1]
+  br i1 undef, label %bb35, label %bb20
+
+bb20:                                             ; preds = %bb18
+  br i1 undef, label %bb21, label %bb25
+
+bb21:                                             ; preds = %bb21, %bb20
+  %tmp28 = getelementptr inbounds %struct.XXXPoint* %positions.0, i32 undef, i32 0 ; <float*> [#uses=1]
+  store float undef, float* %tmp28, align 4
+  %elt22 = getelementptr inbounds %struct.XXXPoint* %advances, i32 undef, i32 1 ; <float*> [#uses=1]
+  %val23 = load float* %elt22                     ; <float> [#uses=0]
+  br i1 undef, label %bb21, label %bb25
+
+bb25:                                             ; preds = %bb21, %bb20
+  switch i32 undef, label %bb26 [
+    i32 4, label %bb27
+    i32 5, label %bb27
+    i32 6, label %bb27
+    i32 7, label %bb28
+  ]
+
+bb26:                                             ; preds = %bb25
+  unreachable
+
+bb27:                                             ; preds = %bb25, %bb25, %bb25
+  unreachable
+
+bb28:                                             ; preds = %bb25
+  unreachable
+
+bb35:                                             ; preds = %bb18, %bb10, %bb7, %bb2
+  ret void
+}