[ARM] Fix handling of thumb1 out-of-range frame offsets

LocalStackSlotPass assumes that isFrameOffsetLegal doesn't change its
answer when the base register changes. Unfortunately this isn't true
in thumb1, where SP-based loads allow a larger offset than
non-SP-based loads, and this causes the base register reuse code to
generate instructions that are unencodable, causing an assertion
failure. 

Solve this by adding a BaseReg parameter to isFrameOffsetLegal, which
ARMBaseRegisterInfo can then make use of to give the correct answer. 

Differential Revision: http://reviews.llvm.org/D8419

llvm-svn: 232825

1 files changed, 37 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/Thumb/stack-access.ll b/llvm/test/CodeGen/Thumb/stack-access.ll
index bc5ecc10b4d..fded4104207 100644
--- a/llvm/test/CodeGen/Thumb/stack-access.ll
+++ b/llvm/test/CodeGen/Thumb/stack-access.ll
@@ -88,3 +88,40 @@ define void @test7() {
 
   ret void
 }
+
+; Check that loads/stores with out-of-range offsets are handled correctly
+define void @test8() {
+  %arr3 = alloca [224 x i32], align 4
+  %arr2 = alloca [224 x i32], align 4
+  %arr1 = alloca [224 x i32], align 4
+
+; CHECK: movs [[REG:r[0-9]+]], #1
+; CHECK: str [[REG]], [sp]
+  %arr1idx1 = getelementptr inbounds [224 x i32], [224 x i32]* %arr1, i32 0, i32 0
+  store i32 1, i32* %arr1idx1, align 4
+
+; Offset in range for sp-based store, but not for non-sp-based store
+; CHECK: str [[REG]], [sp, #128]
+  %arr1idx2 = getelementptr inbounds [224 x i32], [224 x i32]* %arr1, i32 0, i32 32
+  store i32 1, i32* %arr1idx2, align 4
+
+; CHECK: str [[REG]], [sp, #896]
+  %arr2idx1 = getelementptr inbounds [224 x i32], [224 x i32]* %arr2, i32 0, i32 0
+  store i32 1, i32* %arr2idx1, align 4
+
+; %arr2 is in range, but this element of it is not
+; CHECK: str [[REG]], [{{r[0-9]+}}]
+  %arr2idx2 = getelementptr inbounds [224 x i32], [224 x i32]* %arr2, i32 0, i32 32
+  store i32 1, i32* %arr2idx2, align 4
+
+; %arr3 is not in range
+; CHECK: str [[REG]], [{{r[0-9]+}}]
+  %arr3idx1 = getelementptr inbounds [224 x i32], [224 x i32]* %arr3, i32 0, i32 0
+  store i32 1, i32* %arr3idx1, align 4
+
+; CHECK: str [[REG]], [{{r[0-9]+}}]
+  %arr3idx2 = getelementptr inbounds [224 x i32], [224 x i32]* %arr3, i32 0, i32 32
+  store i32 1, i32* %arr3idx2, align 4
+
+  ret void
+}