1 files changed, 65 insertions, 0 deletions
diff --git a/llvm/test/Transforms/SROA/phi-and-select.ll b/llvm/test/Transforms/SROA/phi-and-select.ll
index 8d82964dcbd..9948bb35107 100644
--- a/llvm/test/Transforms/SROA/phi-and-select.ll
+++ b/llvm/test/Transforms/SROA/phi-and-select.ll
@@ -501,3 +501,68 @@ end:
 ; CHECK-NOT: load
 ; CHECK: ret float %[[phi]]
 }
+
+; Verifies we fixed PR20425. We should be able to promote all alloca's to
+; registers in this test.
+;
+; %0 = slice
+; %1 = slice
+; %2 = phi(%0, %1) // == slice
+define float @simplify_phi_nodes_that_equal_slice(i1 %cond, float* %temp) {
+; CHECK-LABEL: @simplify_phi_nodes_that_equal_slice(
+entry:
+  %arr = alloca [4 x float], align 4
+; CHECK-NOT: alloca
+  br i1 %cond, label %then, label %else
+
+then:
+  %0 = getelementptr inbounds [4 x float]* %arr, i64 0, i64 3
+  store float 1.000000e+00, float* %0, align 4
+  br label %merge
+
+else:
+  %1 = getelementptr inbounds [4 x float]* %arr, i64 0, i64 3
+  store float 2.000000e+00, float* %1, align 4
+  br label %merge
+
+merge:
+  %2 = phi float* [ %0, %then ], [ %1, %else ]
+  store float 0.000000e+00, float* %temp, align 4
+  %3 = load float* %2, align 4
+  ret float %3
+}
+
+; A slightly complicated example for PR20425.
+;
+; %0 = slice
+; %1 = phi(%0) // == slice
+; %2 = slice
+; %3 = phi(%1, %2) // == slice
+define float @simplify_phi_nodes_that_equal_slice_2(i1 %cond, float* %temp) {
+; CHECK-LABEL: @simplify_phi_nodes_that_equal_slice_2(
+entry:
+  %arr = alloca [4 x float], align 4
+; CHECK-NOT: alloca
+  br i1 %cond, label %then, label %else
+
+then:
+  %0 = getelementptr inbounds [4 x float]* %arr, i64 0, i64 3
+  store float 1.000000e+00, float* %0, align 4
+  br label %then2
+
+then2:
+  %1 = phi float* [ %0, %then ]
+  store float 2.000000e+00, float* %1, align 4
+  br label %merge
+
+else:
+  %2 = getelementptr inbounds [4 x float]* %arr, i64 0, i64 3
+  store float 3.000000e+00, float* %2, align 4
+  br label %merge
+
+merge:
+  %3 = phi float* [ %1, %then2 ], [ %2, %else ]
+  store float 0.000000e+00, float* %temp, align 4
+  %4 = load float* %3, align 4
+  ret float %4
+}