[fast-isel] Fallback to SelectionDAG isel if we require strict alignment for

non-halfword-aligned i16 loads/stores.
rdar://12304911

llvm-svn: 164345

diff --git a/llvm/lib/Target/ARM/ARMFastISel.cpp b/llvm/lib/Target/ARM/ARMFastISel.cpp
index 045d90424bd225e88add8184388be78165e8f279..af45ed7f4736e5b7cbe97b9999fdad479ef027cb 100644 (file)
--- a/llvm/lib/Target/ARM/ARMFastISel.cpp
+++ b/llvm/lib/Target/ARM/ARMFastISel.cpp
@@ -1021,6 +1021,9 @@ bool ARMFastISel::ARMEmitLoad(EVT VT, unsigned &ResultReg, Address &Addr,
       RC = &ARM::GPRRegClass;
       break;
     case MVT::i16:
+      if (Alignment && Alignment < 2 && !Subtarget->allowsUnalignedMem())
+        return false;
+
       if (isThumb2) {
         if (Addr.Offset < 0 && Addr.Offset > -256 && Subtarget->hasV6T2Ops())
           Opc = isZExt ? ARM::t2LDRHi8 : ARM::t2LDRSHi8;
@@ -1139,6 +1142,9 @@ bool ARMFastISel::ARMEmitStore(EVT VT, unsigned SrcReg, Address &Addr,
       }
       break;
     case MVT::i16:
+      if (Alignment && Alignment < 2 && !Subtarget->allowsUnalignedMem())
+        return false;
+
       if (isThumb2) {
         if (Addr.Offset < 0 && Addr.Offset > -256 && Subtarget->hasV6T2Ops())
           StrOpc = ARM::t2STRHi8;

diff --git a/llvm/test/CodeGen/ARM/fast-isel.ll b/llvm/test/CodeGen/ARM/fast-isel.ll
index ecd5fe27a4b7a7326b6f0c18acf343d6a105082a..075fd2d0d2c62f78760115248286b26680f461d4 100644 (file)
--- a/llvm/test/CodeGen/ARM/fast-isel.ll
+++ b/llvm/test/CodeGen/ARM/fast-isel.ll
@@ -1,5 +1,7 @@
 ; RUN: llc < %s -O0 -fast-isel-abort -relocation-model=dynamic-no-pic -mtriple=armv7-apple-ios | FileCheck %s --check-prefix=ARM
 ; RUN: llc < %s -O0 -fast-isel-abort -relocation-model=dynamic-no-pic -mtriple=thumbv7-apple-ios | FileCheck %s --check-prefix=THUMB
+; RUN: llc < %s -O0 -arm-strict-align -relocation-model=dynamic-no-pic -mtriple=armv7-apple-ios | FileCheck %s --check-prefix=ARM-STRICT-ALIGN
+; RUN: llc < %s -O0 -arm-strict-align -relocation-model=dynamic-no-pic -mtriple=thumbv7-apple-ios | FileCheck %s --check-prefix=THUMB-STRICT-ALIGN
 
 ; Very basic fast-isel functionality.
 define i32 @add(i32 %a, i32 %b) nounwind {
@@ -238,3 +240,31 @@ entry:
 }
 
 declare void @llvm.trap() nounwind
+
+define void @unaligned_i16_store(i16 %x, i16* %y) nounwind {
+entry:
+; ARM-STRICT-ALIGN: @unaligned_i16_store
+; ARM-STRICT-ALIGN: strb
+; ARM-STRICT-ALIGN-NEXT: strb
+
+; THUMB-STRICT-ALIGN: @unaligned_i16_store
+; THUMB-STRICT-ALIGN: strb
+; THUMB-STRICT-ALIGN: strb
+
+  store i16 %x, i16* %y, align 1
+  ret void
+}
+
+define i16 @unaligned_i16_load(i16* %x) nounwind {
+entry:
+; ARM-STRICT-ALIGN: @unaligned_i16_store
+; ARM-STRICT-ALIGN: ldrb
+; ARM-STRICT-ALIGN: ldrb
+
+; THUMB-STRICT-ALIGN: @unaligned_i16_store
+; THUMB-STRICT-ALIGN: ldrb
+; THUMB-STRICT-ALIGN: ldrb
+
+  %0 = load i16* %x, align 1
+  ret i16 %0
+}
\ No newline at end of file