[llvm] r276897 - GlobalISel: support zero-sized allocas

[Tim Northover via llvm-commits]

Author: tnorthover
Date: Wed Jul 27 12:47:54 2016
New Revision: 276897

URL: http://llvm.org/viewvc/llvm-project?rev=276897&view=rev
Log:
GlobalISel: support zero-sized allocas

All allocas must be at least 1 byte at the MachineIR level so we allocate just
one byte.

Modified:
    llvm/trunk/lib/CodeGen/GlobalISel/IRTranslator.cpp
    llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll

Modified: llvm/trunk/lib/CodeGen/GlobalISel/IRTranslator.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/GlobalISel/IRTranslator.cpp?rev=276897&r1=276896&r2=276897&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/GlobalISel/IRTranslator.cpp (original)
+++ llvm/trunk/lib/CodeGen/GlobalISel/IRTranslator.cpp Wed Jul 27 12:47:54 2016
@@ -172,6 +172,9 @@ bool IRTranslator::translateStaticAlloca
   unsigned Size =
       ElementSize * cast<ConstantInt>(AI.getArraySize())->getZExtValue();
 
+  // Always allocate at least one byte.
+  Size = std::max(Size, 1u);
+
   unsigned Alignment = AI.getAlignment();
   if (!Alignment)
     Alignment = DL->getABITypeAlignment(AI.getAllocatedType());

Modified: llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll?rev=276897&r1=276896&r2=276897&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll Wed Jul 27 12:47:54 2016
@@ -23,13 +23,16 @@ define i64 @addi64(i64 %arg1, i64 %arg2)
 ; CHECK-NEXT:   - { id: 0, name: ptr1, offset: 0, size: 8, alignment: 8 }
 ; CHECK-NEXT:   - { id: 1, name: ptr2, offset: 0, size: 8, alignment: 1 }
 ; CHECK-NEXT:   - { id: 2, name: ptr3, offset: 0, size: 128, alignment: 8 }
+; CHECK-NEXT:   - { id: 3, name: ptr4, offset: 0, size: 1, alignment: 8 }
 ; CHECK: %{{[0-9]+}}(64) = G_FRAME_INDEX p0 %stack.0.ptr1
 ; CHECK: %{{[0-9]+}}(64) = G_FRAME_INDEX p0 %stack.1.ptr2
 ; CHECK: %{{[0-9]+}}(64) = G_FRAME_INDEX p0 %stack.2.ptr3
+; CHECK: %{{[0-9]+}}(64) = G_FRAME_INDEX p0 %stack.3.ptr4
 define void @allocai64() {
   %ptr1 = alloca i64
   %ptr2 = alloca i64, align 1
   %ptr3 = alloca i64, i32 16
+  %ptr4 = alloca [0 x i64]
   ret void
 }