[llvm] r310071 - [ArgPromotion] Preserve alignment of byval argument in new alloca

[Reid Kleckner via llvm-commits]

Author: rnk
Date: Fri Aug  4 10:09:11 2017
New Revision: 310071

URL: http://llvm.org/viewvc/llvm-project?rev=310071&view=rev
Log:
[ArgPromotion] Preserve alignment of byval argument in new alloca

The frontend may have requested a higher alignment for any reason, and
downstream optimizations may already have taken advantage of it.  We
should keep the same alignment when moving the allocation from the
parameter area to the local variable area.

Fixes PR34038

Modified:
    llvm/trunk/lib/Transforms/IPO/ArgumentPromotion.cpp
    llvm/trunk/test/Transforms/ArgumentPromotion/byval.ll

Modified: llvm/trunk/lib/Transforms/IPO/ArgumentPromotion.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/ArgumentPromotion.cpp?rev=310071&r1=310070&r2=310071&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/ArgumentPromotion.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/ArgumentPromotion.cpp Fri Aug  4 10:09:11 2017
@@ -356,7 +356,7 @@ doPromotion(Function *F, SmallPtrSetImpl
       // Just add all the struct element types.
       Type *AgTy = cast<PointerType>(I->getType())->getElementType();
       Value *TheAlloca = new AllocaInst(AgTy, DL.getAllocaAddrSpace(), nullptr,
-                                        "", InsertPt);
+                                        I->getParamAlignment(), "", InsertPt);
       StructType *STy = cast<StructType>(AgTy);
       Value *Idxs[2] = {ConstantInt::get(Type::getInt32Ty(F->getContext()), 0),
                         nullptr};

Modified: llvm/trunk/test/Transforms/ArgumentPromotion/byval.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ArgumentPromotion/byval.ll?rev=310071&r1=310070&r2=310071&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/ArgumentPromotion/byval.ll (original)
+++ llvm/trunk/test/Transforms/ArgumentPromotion/byval.ll Fri Aug  4 10:09:11 2017
@@ -6,24 +6,45 @@ target datalayout = "E-p:64:64:64-a0:0:8
 %struct.ss = type { i32, i64 }
 
 define internal void @f(%struct.ss* byval  %b) nounwind  {
+entry:
+  %tmp = getelementptr %struct.ss, %struct.ss* %b, i32 0, i32 0
+  %tmp1 = load i32, i32* %tmp, align 4
+  %tmp2 = add i32 %tmp1, 1
+  store i32 %tmp2, i32* %tmp, align 4
+  ret void
+}
+
 ; CHECK-LABEL: define internal void @f(i32 %b.0, i64 %b.1)
+; CHECK: alloca %struct.ss{{$}}
+; CHECK: store i32 %b.0
+; CHECK: store i64 %b.1
+
+define internal void @g(%struct.ss* byval align 32 %b) nounwind {
 entry:
-  %tmp = getelementptr %struct.ss, %struct.ss* %b, i32 0, i32 0		; <i32*> [#uses=2]
-  %tmp1 = load i32, i32* %tmp, align 4		; <i32> [#uses=1]
-  %tmp2 = add i32 %tmp1, 1		; <i32> [#uses=1]
+  %tmp = getelementptr %struct.ss, %struct.ss* %b, i32 0, i32 0
+  %tmp1 = load i32, i32* %tmp, align 4
+  %tmp2 = add i32 %tmp1, 1
   store i32 %tmp2, i32* %tmp, align 4
   ret void
 }
 
+; CHECK-LABEL: define internal void @g(i32 %b.0, i64 %b.1)
+; CHECK: alloca %struct.ss, align 32
+; CHECK: store i32 %b.0
+; CHECK: store i64 %b.1
+
 define i32 @main() nounwind  {
-; CHECK-LABEL: define i32 @main
 entry:
-  %S = alloca %struct.ss		; <%struct.ss*> [#uses=4]
-  %tmp1 = getelementptr %struct.ss, %struct.ss* %S, i32 0, i32 0		; <i32*> [#uses=1]
+  %S = alloca %struct.ss
+  %tmp1 = getelementptr %struct.ss, %struct.ss* %S, i32 0, i32 0
   store i32 1, i32* %tmp1, align 8
-  %tmp4 = getelementptr %struct.ss, %struct.ss* %S, i32 0, i32 1		; <i64*> [#uses=1]
+  %tmp4 = getelementptr %struct.ss, %struct.ss* %S, i32 0, i32 1
   store i64 2, i64* %tmp4, align 4
-  call void @f( %struct.ss* byval  %S ) nounwind 
-; CHECK: call void @f(i32 %{{.*}}, i64 %{{.*}})
+  call void @f(%struct.ss* byval %S) nounwind
+  call void @g(%struct.ss* byval %S) nounwind
   ret i32 0
 }
+
+; CHECK-LABEL: define i32 @main
+; CHECK: call void @f(i32 %{{.*}}, i64 %{{.*}})
+; CHECK: call void @g(i32 %{{.*}}, i64 %{{.*}})