From: James Molloy <james.molloy@arm.com>
Date: Wed, 7 May 2014 17:41:15 +0000 (+0000)
Subject: When doing int<->ptr coercion for big-endian, calculate the shift amount correctly.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=7bb93d64a69ee417a4f7f63ae6caffa59037ec53;p=clang

When doing int<->ptr coercion for big-endian, calculate the shift amount correctly.

Previously we calculated the shift amount based upon DataLayout::getTypeAllocSizeInBits.
This will only work for legal types - types such as i24 that are created as part of
structs for bitfields will return "32" from that function. Change to using
getTypeSizeInBits.

It turns out that AArch64 didn't run across this problem because it always returned
[1 x i64] as the type for a bitfield, whereas ARM64 returns i64 so goes down this
(better, but wrong) codepath.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@208231 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index da50473983..972a7c8dbb 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -700,8 +700,9 @@ static llvm::Value *CoerceIntOrPtrToIntOrPtr(llvm::Value *Val,
     if (DL.isBigEndian()) {
       // Preserve the high bits on big-endian targets.
       // That is what memory coercion does.
-      uint64_t SrcSize = DL.getTypeAllocSizeInBits(Val->getType());
-      uint64_t DstSize = DL.getTypeAllocSizeInBits(DestIntTy);
+      uint64_t SrcSize = DL.getTypeSizeInBits(Val->getType());
+      uint64_t DstSize = DL.getTypeSizeInBits(DestIntTy);
+
       if (SrcSize > DstSize) {
         Val = CGF.Builder.CreateLShr(Val, SrcSize - DstSize, "coerce.highbits");
         Val = CGF.Builder.CreateTrunc(Val, DestIntTy, "coerce.val.ii");
diff --git a/test/CodeGen/arm64-be-bitfield.c b/test/CodeGen/arm64-be-bitfield.c
new file mode 100644
index 0000000000..f563596bdd
--- /dev/null
+++ b/test/CodeGen/arm64-be-bitfield.c
@@ -0,0 +1,9 @@
+// RUN:  %clang_cc1 -triple arm64_be-linux-gnu -ffreestanding -emit-llvm -O0 -o - %s | FileCheck %s
+
+struct bt3 { signed b2:10; signed b3:10; } b16;
+
+// The correct right-shift amount is 40 bits for big endian.
+signed callee_b0f(struct bt3 bp11) {
+// CHECK: = lshr i64 %{{.*}}, 40
+  return bp11.b2;
+}