[X86][FastISel] During X86 fastisel, the address of indirect call was resolved

through bitcast, ptrtoint, and inttoptr instructions. This is valid
only if the related instructions are in that same basic block, otherwise
we may reference variables that were not live accross basic blocks
resulting in undefined virtual registers.

The bug was exposed when both SDISel and FastISel were used within the same
function, i.e., one basic block is issued with FastISel and another with SDISel,
as demonstrated with the testcase.

<rdar://problem/15192473>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192636 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 132 insertions, 0 deletions

diff --git a/test/CodeGen/X86/2013-10-14-FastISel-incorrect-vreg.ll b/test/CodeGen/X86/2013-10-14-FastISel-incorrect-vreg.ll
new file mode 100644
index 0000000000..3455b68fb0
--- /dev/null
+++ b/test/CodeGen/X86/2013-10-14-FastISel-incorrect-vreg.ll
@@ -0,0 +1,132 @@
+; RUN: llc -mtriple x86_64-apple-darwin -O0 < %s -o - | FileCheck %s
+;
+; During X86 fastisel, the address of indirect call was resolved
+; through bitcast, ptrtoint, and inttoptr instructions. This is valid
+; only if the related instructions are in that same basic block, otherwise
+; we may reference variables that were not live accross basic blocks
+; resulting in undefined virtual registers.
+;
+; In this example, this is illustrated by a the spill/reload of the
+; LOADED_PTR_SLOT.
+;
+; Before this patch, the compiler was accessing two different spill
+; slots.
+; <rdar://problem/15192473>
+
+; CHECK-LABEL: @test_bitcast
+; Load the value of the function pointer: %loaded_ptr
+; CHECK: movq (%rdi), [[LOADED_PTR:%[a-z]+]]
+; Spill %arg2.
+; CHECK: movq %rdx, [[ARG2_SLOT:[0-9]*\(%[a-z]+\)]]
+; Spill %loaded_ptr.
+; CHECK: movq [[LOADED_PTR]], [[LOADED_PTR_SLOT:[0-9]*\(%[a-z]+\)]]
+; Perform the indirect call.
+; Load the first argument
+; CHECK: movq [[ARG2_SLOT]], %rdi
+; Load the second argument
+; CHECK: movq [[ARG2_SLOT]], %rsi
+; Load the thrid argument
+; CHECK: movq [[ARG2_SLOT]], %rdx
+; Load the function pointer.
+; CHECK: movq [[LOADED_PTR_SLOT]], [[FCT_PTR:%[a-z]+]]
+; Call.
+; CHECK: callq *[[FCT_PTR]]
+; CHECK: ret
+define i64 @test_bitcast(i64 (i64, i64, i64)** %arg, i1 %bool, i64 %arg2) {
+entry:
+  %loaded_ptr = load i64 (i64, i64, i64)** %arg, align 8
+  %raw = bitcast i64 (i64, i64, i64)* %loaded_ptr to i8*
+  switch i1 %bool, label %default [
+    i1 true, label %label_true
+    i1 false, label %label_end
+  ]
+default:
+  unreachable
+
+label_true:
+  br label %label_end
+
+label_end:
+  %fct_ptr = bitcast i8* %raw to i64 (i64, i64, i64)*
+  %res = call i64 %fct_ptr(i64 %arg2, i64 %arg2, i64 %arg2)
+  ret i64 %res
+}
+
+; CHECK-LABEL: @test_inttoptr
+; Load the value of the function pointer: %loaded_ptr
+; CHECK: movq (%rdi), [[LOADED_PTR:%[a-z]+]]
+; Spill %arg2.
+; CHECK: movq %rdx, [[ARG2_SLOT:[0-9]*\(%[a-z]+\)]]
+; Spill %loaded_ptr.
+; CHECK: movq [[LOADED_PTR]], [[LOADED_PTR_SLOT:[0-9]*\(%[a-z]+\)]]
+; Perform the indirect call.
+; Load the first argument
+; CHECK: movq [[ARG2_SLOT]], %rdi
+; Load the second argument
+; CHECK: movq [[ARG2_SLOT]], %rsi
+; Load the thrid argument
+; CHECK: movq [[ARG2_SLOT]], %rdx
+; Load the function pointer.
+; CHECK: movq [[LOADED_PTR_SLOT]], [[FCT_PTR:%[a-z]+]]
+; Call.
+; CHECK: callq *[[FCT_PTR]]
+; CHECK: ret
+define i64 @test_inttoptr(i64 (i64, i64, i64)** %arg, i1 %bool, i64 %arg2) {
+entry:
+  %loaded_ptr = load i64 (i64, i64, i64)** %arg, align 8
+  %raw = ptrtoint i64 (i64, i64, i64)* %loaded_ptr to i64
+  switch i1 %bool, label %default [
+    i1 true, label %label_true
+    i1 false, label %label_end
+  ]
+default:
+  unreachable
+
+label_true:
+  br label %label_end
+
+label_end:
+  %fct_ptr = inttoptr i64 %raw to i64 (i64, i64, i64)*
+  %res = call i64 %fct_ptr(i64 %arg2, i64 %arg2, i64 %arg2)
+  ret i64 %res
+}
+
+; CHECK-LABEL: @test_ptrtoint
+; Load the value of the function pointer: %loaded_ptr
+; CHECK: movq (%rdi), [[LOADED_PTR:%[a-z]+]]
+; Spill %arg2.
+; CHECK: movq %rdx, [[ARG2_SLOT:[0-9]*\(%[a-z]+\)]]
+; Spill %loaded_ptr.
+; CHECK: movq [[LOADED_PTR]], [[LOADED_PTR_SLOT:[0-9]*\(%[a-z]+\)]]
+; Perform the indirect call.
+; Load the first argument
+; CHECK: movq [[ARG2_SLOT]], %rdi
+; Load the second argument
+; CHECK: movq [[ARG2_SLOT]], %rsi
+; Load the thrid argument
+; CHECK: movq [[ARG2_SLOT]], %rdx
+; Load the function pointer.
+; CHECK: movq [[LOADED_PTR_SLOT]], [[FCT_PTR:%[a-z]+]]
+; Call.
+; CHECK: callq *[[FCT_PTR]]
+; CHECK: ret
+define i64 @test_ptrtoint(i64 (i64, i64, i64)** %arg, i1 %bool, i64 %arg2) {
+entry:
+  %loaded_ptr = load i64 (i64, i64, i64)** %arg, align 8
+  %raw = bitcast i64 (i64, i64, i64)* %loaded_ptr to i8*
+  switch i1 %bool, label %default [
+    i1 true, label %label_true
+    i1 false, label %label_end
+  ]
+default:
+  unreachable
+
+label_true:
+  br label %label_end
+
+label_end:
+  %fct_int = ptrtoint i8* %raw to i64
+  %fct_ptr = inttoptr i64 %fct_int to i64 (i64, i64, i64)*
+  %res = call i64 %fct_ptr(i64 %arg2, i64 %arg2, i64 %arg2)
+  ret i64 %res
+}