[llvm-commits] [llvm] r123380 - in /llvm/trunk: lib/Transforms/Scalar/ScalarReplAggregates.cpp test/Transforms/ScalarRepl/copy-aggregate.ll
Bob Wilson
bob.wilson at apple.com
Thu Jan 13 09:45:08 PST 2011
Author: bwilson
Date: Thu Jan 13 11:45:08 2011
New Revision: 123380
URL: http://llvm.org/viewvc/llvm-project?rev=123380&view=rev
Log:
Make SROA more aggressive with allocas containing padding.
SROA only split up structs and arrays one level at a time, so padding can
only cause trouble if it is located in between the struct or array elements.
Modified:
llvm/trunk/lib/Transforms/Scalar/ScalarReplAggregates.cpp
llvm/trunk/test/Transforms/ScalarRepl/copy-aggregate.ll
Modified: llvm/trunk/lib/Transforms/Scalar/ScalarReplAggregates.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/ScalarReplAggregates.cpp?rev=123380&r1=123379&r2=123380&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/ScalarReplAggregates.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/ScalarReplAggregates.cpp Thu Jan 13 11:45:08 2011
@@ -1676,46 +1676,39 @@
}
/// HasPadding - Return true if the specified type has any structure or
-/// alignment padding, false otherwise.
+/// alignment padding in between the elements that would be split apart
+/// by SROA; return false otherwise.
static bool HasPadding(const Type *Ty, const TargetData &TD) {
- if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty))
- return HasPadding(ATy->getElementType(), TD);
-
- if (const VectorType *VTy = dyn_cast<VectorType>(Ty))
- return HasPadding(VTy->getElementType(), TD);
-
- if (const StructType *STy = dyn_cast<StructType>(Ty)) {
- const StructLayout *SL = TD.getStructLayout(STy);
- unsigned PrevFieldBitOffset = 0;
- for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
- unsigned FieldBitOffset = SL->getElementOffsetInBits(i);
-
- // Padding in sub-elements?
- if (HasPadding(STy->getElementType(i), TD))
- return true;
+ if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
+ Ty = ATy->getElementType();
+ return TD.getTypeSizeInBits(Ty) != TD.getTypeAllocSizeInBits(Ty);
+ }
- // Check to see if there is any padding between this element and the
- // previous one.
- if (i) {
- unsigned PrevFieldEnd =
+ // SROA currently handles only Arrays and Structs.
+ const StructType *STy = cast<StructType>(Ty);
+ const StructLayout *SL = TD.getStructLayout(STy);
+ unsigned PrevFieldBitOffset = 0;
+ for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
+ unsigned FieldBitOffset = SL->getElementOffsetInBits(i);
+
+ // Check to see if there is any padding between this element and the
+ // previous one.
+ if (i) {
+ unsigned PrevFieldEnd =
PrevFieldBitOffset+TD.getTypeSizeInBits(STy->getElementType(i-1));
- if (PrevFieldEnd < FieldBitOffset)
- return true;
- }
-
- PrevFieldBitOffset = FieldBitOffset;
- }
-
- // Check for tail padding.
- if (unsigned EltCount = STy->getNumElements()) {
- unsigned PrevFieldEnd = PrevFieldBitOffset +
- TD.getTypeSizeInBits(STy->getElementType(EltCount-1));
- if (PrevFieldEnd < SL->getSizeInBits())
+ if (PrevFieldEnd < FieldBitOffset)
return true;
}
+ PrevFieldBitOffset = FieldBitOffset;
}
-
- return TD.getTypeSizeInBits(Ty) != TD.getTypeAllocSizeInBits(Ty);
+ // Check for tail padding.
+ if (unsigned EltCount = STy->getNumElements()) {
+ unsigned PrevFieldEnd = PrevFieldBitOffset +
+ TD.getTypeSizeInBits(STy->getElementType(EltCount-1));
+ if (PrevFieldEnd < SL->getSizeInBits())
+ return true;
+ }
+ return false;
}
/// isSafeStructAllocaToScalarRepl - Check to see if the specified allocation of
Modified: llvm/trunk/test/Transforms/ScalarRepl/copy-aggregate.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ScalarRepl/copy-aggregate.ll?rev=123380&r1=123379&r2=123380&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/ScalarRepl/copy-aggregate.ll (original)
+++ llvm/trunk/test/Transforms/ScalarRepl/copy-aggregate.ll Thu Jan 13 11:45:08 2011
@@ -1,9 +1,11 @@
-; RUN: opt < %s -scalarrepl -S | not grep alloca
+; RUN: opt < %s -scalarrepl -S | FileCheck %s
; PR3290
target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64"
;; Store of integer to whole alloca struct.
define i32 @test1(i64 %V) nounwind {
+; CHECK: test1
+; CHECK-NOT: alloca
%X = alloca {{i32, i32}}
%Y = bitcast {{i32,i32}}* %X to i64*
store i64 %V, i64* %Y
@@ -18,6 +20,8 @@
;; Store of integer to whole struct/array alloca.
define float @test2(i128 %V) nounwind {
+; CHECK: test2
+; CHECK-NOT: alloca
%X = alloca {[4 x float]}
%Y = bitcast {[4 x float]}* %X to i128*
store i128 %V, i128* %Y
@@ -32,6 +36,8 @@
;; Load of whole alloca struct as integer
define i64 @test3(i32 %a, i32 %b) nounwind {
+; CHECK: test3
+; CHECK-NOT: alloca
%X = alloca {{i32, i32}}
%A = getelementptr {{i32,i32}}* %X, i32 0, i32 0, i32 0
@@ -46,6 +52,8 @@
;; load of integer from whole struct/array alloca.
define i128 @test4(float %a, float %b) nounwind {
+; CHECK: test4
+; CHECK-NOT: alloca
%X = alloca {[4 x float]}
%A = getelementptr {[4 x float]}* %X, i32 0, i32 0, i32 0
%B = getelementptr {[4 x float]}* %X, i32 0, i32 0, i32 3
@@ -56,3 +64,22 @@
%V = load i128* %Y
ret i128 %V
}
+
+;; If the elements of a struct or array alloca contain padding, SROA can still
+;; split up the alloca as long as there is no padding between the elements.
+%padded = type { i16, i8 }
+%arr = type [4 x %padded]
+define void @test5(%arr* %p, %arr* %q) {
+entry:
+; CHECK: test5
+; CHECK-NOT: i128
+ %var = alloca %arr, align 4
+ %vari8 = bitcast %arr* %var to i8*
+ %pi8 = bitcast %arr* %p to i8*
+ call void @llvm.memcpy.i32(i8* %vari8, i8* %pi8, i32 16, i32 4)
+ %qi8 = bitcast %arr* %q to i8*
+ call void @llvm.memcpy.i32(i8* %qi8, i8* %vari8, i32 16, i32 4)
+ ret void
+}
+
+declare void @llvm.memcpy.i32(i8* nocapture, i8* nocapture, i32, i32) nounwind
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