[clang] [clang] Avoid memcopy for small structure with padding (PR #71677)
via cfe-commits
cfe-commits at lists.llvm.org
Wed Nov 8 06:36:22 PST 2023
https://github.com/serge-sans-paille updated https://github.com/llvm/llvm-project/pull/71677
>From a35d351a8eb811ed59734ea49c8f912771ef5c2e Mon Sep 17 00:00:00 2001
From: serge-sans-paille <sguelton at mozilla.com>
Date: Wed, 8 Nov 2023 10:26:33 +0100
Subject: [PATCH 1/2] [clang] Avoid memcopy for small structure with padding
under -ftrivial-auto-var-init
---
clang/lib/CodeGen/CGDecl.cpp | 19 ++++++------
clang/test/CodeGenCXX/auto-var-init.cpp | 39 ++++++++++++-------------
2 files changed, 29 insertions(+), 29 deletions(-)
diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index e5795d811c76de7..9761ae4726dc14e 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -1244,17 +1244,18 @@ static void emitStoresForConstant(CodeGenModule &CGM, const VarDecl &D,
// If the initializer is small, use a handful of stores.
if (shouldSplitConstantStore(CGM, ConstantSize)) {
if (auto *STy = dyn_cast<llvm::StructType>(Ty)) {
- // FIXME: handle the case when STy != Loc.getElementType().
- if (STy == Loc.getElementType()) {
- for (unsigned i = 0; i != constant->getNumOperands(); i++) {
- Address EltPtr = Builder.CreateStructGEP(Loc, i);
- emitStoresForConstant(
- CGM, D, EltPtr, isVolatile, Builder,
- cast<llvm::Constant>(Builder.CreateExtractValue(constant, i)),
- IsAutoInit);
+ const llvm::StructLayout *Layout = CGM.getDataLayout().getStructLayout(
+ cast<llvm::StructType>(constant->getType()));
+ for (unsigned i = 0; i != constant->getNumOperands(); i++) {
+ CharUnits CurOff = CharUnits::fromQuantity(Layout->getElementOffset(i));
+ Address EltPtr = Builder.CreateConstInBoundsByteGEP(
+ Loc.withElementType(CGM.Int8Ty), CurOff);
+ emitStoresForConstant(
+ CGM, D, EltPtr, isVolatile, Builder,
+ cast<llvm::Constant>(Builder.CreateExtractValue(constant, i)),
+ IsAutoInit);
}
return;
- }
} else if (auto *ATy = dyn_cast<llvm::ArrayType>(Ty)) {
// FIXME: handle the case when ATy != Loc.getElementType().
if (ATy == Loc.getElementType()) {
diff --git a/clang/test/CodeGenCXX/auto-var-init.cpp b/clang/test/CodeGenCXX/auto-var-init.cpp
index 6cb18528ebadcdf..75a137f461b27d1 100644
--- a/clang/test/CodeGenCXX/auto-var-init.cpp
+++ b/clang/test/CodeGenCXX/auto-var-init.cpp
@@ -89,22 +89,14 @@ struct padded { char c; int i; };
// PATTERN-O1-NOT: @__const.test_paddednullinit_custom.custom
struct paddednullinit { char c = 0; int i = 0; };
// PATTERN-O0: @__const.test_paddedpacked_uninit.uninit = private unnamed_addr constant %struct.paddedpacked <{ i8 [[I8]], i32 [[I32]] }>, align 1
-// PATTERN: @__const.test_paddedpacked_custom.custom = private unnamed_addr constant %struct.paddedpacked <{ i8 42, i32 13371337 }>, align 1
-// ZERO: @__const.test_paddedpacked_custom.custom = private unnamed_addr constant %struct.paddedpacked <{ i8 42, i32 13371337 }>, align 1
struct paddedpacked { char c; int i; } __attribute__((packed));
// PATTERN-O0: @__const.test_paddedpackedarray_uninit.uninit = private unnamed_addr constant %struct.paddedpackedarray { [2 x %struct.paddedpacked] [%struct.paddedpacked <{ i8 [[I8]], i32 [[I32]] }>, %struct.paddedpacked <{ i8 [[I8]], i32 [[I32]] }>] }, align 1
-// PATTERN: @__const.test_paddedpackedarray_custom.custom = private unnamed_addr constant %struct.paddedpackedarray { [2 x %struct.paddedpacked] [%struct.paddedpacked <{ i8 42, i32 13371337 }>, %struct.paddedpacked <{ i8 43, i32 13371338 }>] }, align 1
-// ZERO: @__const.test_paddedpackedarray_custom.custom = private unnamed_addr constant %struct.paddedpackedarray { [2 x %struct.paddedpacked] [%struct.paddedpacked <{ i8 42, i32 13371337 }>, %struct.paddedpacked <{ i8 43, i32 13371338 }>] }, align 1
struct paddedpackedarray { struct paddedpacked p[2]; };
// PATTERN-O0: @__const.test_unpackedinpacked_uninit.uninit = private unnamed_addr constant <{ { i8, [3 x i8], i32 }, i8 }> <{ { i8, [3 x i8], i32 } { i8 [[I8]], [3 x i8] c"\[[IC]]\[[IC]]\[[IC]]", i32 [[I32]] }, i8 [[I8]] }>, align 1
struct unpackedinpacked { padded a; char b; } __attribute__((packed));
// PATTERN-O0: @__const.test_paddednested_uninit.uninit = private unnamed_addr constant { { i8, [3 x i8], i32 }, { i8, [3 x i8], i32 } } { { i8, [3 x i8], i32 } { i8 [[I8]], [3 x i8] c"\[[IC]]\[[IC]]\[[IC]]", i32 [[I32]] }, { i8, [3 x i8], i32 } { i8 [[I8]], [3 x i8] c"\[[IC]]\[[IC]]\[[IC]]", i32 [[I32]] } }, align 4
-// PATTERN: @__const.test_paddednested_custom.custom = private unnamed_addr constant { { i8, [3 x i8], i32 }, { i8, [3 x i8], i32 } } { { i8, [3 x i8], i32 } { i8 42, [3 x i8] zeroinitializer, i32 13371337 }, { i8, [3 x i8], i32 } { i8 43, [3 x i8] zeroinitializer, i32 13371338 } }, align 4
-// ZERO: @__const.test_paddednested_custom.custom = private unnamed_addr constant { { i8, [3 x i8], i32 }, { i8, [3 x i8], i32 } } { { i8, [3 x i8], i32 } { i8 42, [3 x i8] zeroinitializer, i32 13371337 }, { i8, [3 x i8], i32 } { i8 43, [3 x i8] zeroinitializer, i32 13371338 } }, align 4
struct paddednested { struct padded p1, p2; };
// PATTERN-O0: @__const.test_paddedpackednested_uninit.uninit = private unnamed_addr constant %struct.paddedpackednested { %struct.paddedpacked <{ i8 [[I8]], i32 [[I32]] }>, %struct.paddedpacked <{ i8 [[I8]], i32 [[I32]] }> }, align 1
-// PATTERN: @__const.test_paddedpackednested_custom.custom = private unnamed_addr constant %struct.paddedpackednested { %struct.paddedpacked <{ i8 42, i32 13371337 }>, %struct.paddedpacked <{ i8 43, i32 13371338 }> }, align 1
-// ZERO: @__const.test_paddedpackednested_custom.custom = private unnamed_addr constant %struct.paddedpackednested { %struct.paddedpacked <{ i8 42, i32 13371337 }>, %struct.paddedpacked <{ i8 43, i32 13371338 }> }, align 1
struct paddedpackednested { struct paddedpacked p1, p2; };
// PATTERN-O0: @__const.test_bitfield_uninit.uninit = private unnamed_addr constant %struct.bitfield { i8 [[I8]], [3 x i8] c"\[[IC]]\[[IC]]\[[IC]]" }, align 4
// PATTERN-O0: @__const.test_bitfield_custom.custom = private unnamed_addr constant %struct.bitfield { i8 20, [3 x i8] c"\[[IC]]\[[IC]]\[[IC]]" }, align 4
@@ -714,7 +706,8 @@ TEST_UNINIT(padded, padded);
// CHECK-NEXT: call void @{{.*}}used{{.*}}%uninit)
// PATTERN-LABEL: @test_padded_uninit()
// PATTERN-O0: call void @llvm.memcpy{{.*}} @__const.test_padded_uninit.uninit{{.+}}), !annotation [[AUTO_INIT]]
-// PATTERN-O1: store i64 [[I64]], ptr %uninit, align 8, !annotation [[AUTO_INIT]]
+// PATTERN-O1: store i64 [[I64]], ptr %uninit, align 8
+// PATTERN-O1-NOT: !annotation
// ZERO-LABEL: @test_padded_uninit()
// ZERO-O0: call void @llvm.memset{{.*}}, i8 0,{{.+}}), !annotation [[AUTO_INIT]]
// ZERO-O1: store i64 0, ptr %uninit, align 8, !annotation [[AUTO_INIT]]
@@ -740,7 +733,8 @@ TEST_UNINIT(paddednullinit, paddednullinit);
// CHECK-NEXT: call void @{{.*}}used{{.*}}%uninit)
// PATTERN-LABEL: @test_paddednullinit_uninit()
// PATTERN-O0: call void @llvm.memcpy{{.*}} @__const.test_paddednullinit_uninit.uninit{{.+}}), !annotation [[AUTO_INIT]]
-// PATTERN-O1: store i64 [[I64]], ptr %uninit, align 8, !annotation [[AUTO_INIT]]
+// PATTERN-O1: store i64 [[I64]], ptr %uninit, align 8
+// PATTERN-O1-NOT: !annotation
// ZERO-LABEL: @test_paddednullinit_uninit()
// ZERO-O0: call void @llvm.memset{{.*}}, i8 0, {{.*}}, !annotation [[AUTO_INIT]]
// ZERO-O1: store i64 0, ptr %uninit, align 8
@@ -778,9 +772,8 @@ TEST_UNINIT(paddedpacked, paddedpacked);
// PATTERN-LABEL: @test_paddedpacked_uninit()
// PATTERN-O0: call void @llvm.memcpy{{.*}} @__const.test_paddedpacked_uninit.uninit{{.+}}), !annotation [[AUTO_INIT]]
// PATTERN-O1: store i8 [[I8]], ptr %uninit, align {{.+}}, !annotation [[AUTO_INIT]]
-// PATTERN-O1: %[[I:[^ ]*]] = getelementptr inbounds {{.*}}%uninit, i64 0, i32 1
+// PATTERN-O1: %[[I:[^ ]*]] = getelementptr inbounds {{.*}}%uninit, i64 1
// PATTERN-O1: store i32 [[I32]], ptr %[[I]], align {{.+}}, !annotation [[AUTO_INIT]]
-
// ZERO-LABEL: @test_paddedpacked_uninit()
// ZERO: call void @llvm.memset{{.*}}, i8 0,{{.+}}), !annotation [[AUTO_INIT]]
@@ -1192,7 +1185,8 @@ TEST_UNINIT(atomicpadded, _Atomic(padded));
// CHECK-NEXT: call void @{{.*}}used{{.*}}%uninit)
// PATTERN-LABEL: @test_atomicpadded_uninit()
// PATTERN-O0: call void @llvm.memcpy{{.*}} @__const.test_atomicpadded_uninit.uninit{{.+}}), !annotation [[AUTO_INIT]]
-// PATTERN-O1: store i64 [[IPTR]], ptr %uninit, align 8, !annotation [[AUTO_INIT]]
+// PATTERN-O1: store i64 [[IPTR]], ptr %uninit, align 8
+// PATTERN-O1-NOT: !annotation
// ZERO-LABEL: @test_atomicpadded_uninit()
// ZERO-O0: call void @llvm.memset{{.*}}, i8 0, {{.+}}), !annotation [[AUTO_INIT]]
// ZERO-O1: store i64 0, ptr %uninit, align 8, !annotation [[AUTO_INIT]]
@@ -1214,8 +1208,7 @@ TEST_UNINIT(complexfloat, _Complex float);
// PATTERN-LABEL: @test_complexfloat_uninit()
// PATTERN-O0: call void @llvm.memcpy{{.*}} @__const.test_complexfloat_uninit.uninit{{.+}}), !annotation [[AUTO_INIT]]
// PATTERN-O1: store float 0xFFFFFFFFE0000000, ptr %uninit, align {{.+}}, !annotation [[AUTO_INIT]]
-
-// PATTERN-O1: %[[F2:[^ ]*]] = getelementptr inbounds {{.*}}%uninit, i64 0, i32 1
+// PATTERN-O1: %[[F2:[^ ]*]] = getelementptr inbounds {{.*}}%uninit, i64 4
// PATTERN-O1: store float 0xFFFFFFFFE0000000, ptr %[[F2]], align {{.+}}, !annotation [[AUTO_INIT]]
// ZERO-LABEL: @test_complexfloat_uninit()
@@ -1314,7 +1307,9 @@ TEST_CUSTOM(semivolatile, semivolatile, { 0x44444444, 0x44444444 });
// CHECK-O0: call void @llvm.memcpy
// CHECK-NOT: !annotation
// CHECK-O0: call void @{{.*}}used{{.*}}%custom)
-// CHECK-O1: store i64 4919131752989213764, ptr %custom, align 8
+// CHECK-O1: store i32 1145324612, ptr %custom, align 4
+// CHECK-O1-NEXT: %[[I:[^ ]*]] = getelementptr inbounds i8, ptr %custom, i64 4
+// CHECK-O1-NEXT: store i32 1145324612, ptr %[[I]], align 4
// CHECK-NOT: !annotation
TEST_UNINIT(semivolatileinit, semivolatileinit);
@@ -1427,7 +1422,7 @@ TEST_CUSTOM(matching, matching, { .f = 0xf00f });
// CHECK-O0: call void @llvm.memcpy
// CHECK-NOT: !annotation
// CHECK-O0: call void @{{.*}}used{{.*}}%custom)
-// CHECK-O1: store i32 1198526208, ptr {{.*}}, align 4
+// CHECK-O1: store float 6.145500e+04, ptr {{.*}}, align 4
// CHECK-NOT: !annotation
TEST_UNINIT(matchingreverse, matchingreverse);
@@ -1506,8 +1501,12 @@ TEST_CUSTOM(unmatchedreverse, unmatchedreverse, { .c = 42 });
// CHECK-O0: call void @llvm.memcpy
// CHECK-NOT: !annotation
// CHECK-O0: call void @{{.*}}used{{.*}}%custom)
-// PATTERN-O1: store i32 -1431655894, ptr {{.*}}, align 4
-// ZERO-O1: store i32 42, ptr {{.*}}, align 4
+// PATTERN-O1: store i8 42, ptr {{.*}}, align 4
+// PATTERN-O1-NEXT: %[[I:[^ ]*]] = getelementptr inbounds i8, ptr %custom, i64 1
+// PATTERN-O1-NEXT: call void @llvm.memset.{{.*}}({{.*}}, i8 -86, i64 3, {{.*}})
+// ZERO-O1: store i8 42, ptr {{.*}}, align 4
+// ZERO-O1-NEXT: %[[I:[^ ]*]] = getelementptr inbounds i8, ptr %custom, i64 1
+// ZERO-O1-NEXT: call void @llvm.memset.{{.*}}({{.*}}, i8 0, i64 3, {{.*}})
TEST_UNINIT(unmatchedfp, unmatchedfp);
// CHECK-LABEL: @test_unmatchedfp_uninit()
@@ -1532,7 +1531,7 @@ TEST_CUSTOM(unmatchedfp, unmatchedfp, { .d = 3.1415926535897932384626433 });
// CHECK-O0: call void @llvm.memcpy
// CHECK-NOT: !annotation
// CHECK-O0: call void @{{.*}}used{{.*}}%custom)
-// CHECK-O1: store i64 4614256656552045848, ptr %custom, align 8
+// CHECK-O1: store double 0x400921FB54442D18, ptr %custom, align 8
// CHECK-NOT: !annotation
TEST_UNINIT(emptyenum, emptyenum);
>From 7ebf51fc7ff305be93edaabba17e23a73ce7c092 Mon Sep 17 00:00:00 2001
From: serge-sans-paille <sguelton at mozilla.com>
Date: Wed, 8 Nov 2023 15:35:05 +0100
Subject: [PATCH 2/2] [clang] Avoid memcopy for small arrays with padding under
-ftrivial-auto-var-init
---
clang/lib/CodeGen/CGDecl.cpp | 6 ++----
clang/test/CodeGenCXX/auto-var-init.cpp | 10 +++++-----
2 files changed, 7 insertions(+), 9 deletions(-)
diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 9761ae4726dc14e..4fcb73fe077252e 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -1257,17 +1257,15 @@ static void emitStoresForConstant(CodeGenModule &CGM, const VarDecl &D,
}
return;
} else if (auto *ATy = dyn_cast<llvm::ArrayType>(Ty)) {
- // FIXME: handle the case when ATy != Loc.getElementType().
- if (ATy == Loc.getElementType()) {
for (unsigned i = 0; i != ATy->getNumElements(); i++) {
- Address EltPtr = Builder.CreateConstArrayGEP(Loc, i);
+ Address EltPtr = Builder.CreateConstGEP(
+ Loc.withElementType(ATy->getElementType()), i);
emitStoresForConstant(
CGM, D, EltPtr, isVolatile, Builder,
cast<llvm::Constant>(Builder.CreateExtractValue(constant, i)),
IsAutoInit);
}
return;
- }
}
}
diff --git a/clang/test/CodeGenCXX/auto-var-init.cpp b/clang/test/CodeGenCXX/auto-var-init.cpp
index 75a137f461b27d1..e5a9d015f22f276 100644
--- a/clang/test/CodeGenCXX/auto-var-init.cpp
+++ b/clang/test/CodeGenCXX/auto-var-init.cpp
@@ -134,12 +134,8 @@ struct arraytail { int i; int arr[]; };
// PATTERN-O1-NOT: @__const.test_bool4_custom.custom
// ZERO-O1-NOT: @__const.test_bool4_custom.custom
-// PATTERN: @__const.test_intptr4_custom.custom = private unnamed_addr constant [4 x ptr] [ptr inttoptr ([[IPTRT]] 572662306 to ptr), ptr inttoptr ([[IPTRT]] 572662306 to ptr), ptr inttoptr ([[IPTRT]] 572662306 to ptr), ptr inttoptr ([[IPTRT]] 572662306 to ptr)], align
-// ZERO: @__const.test_intptr4_custom.custom = private unnamed_addr constant [4 x ptr] [ptr inttoptr (i64 572662306 to ptr), ptr inttoptr (i64 572662306 to ptr), ptr inttoptr (i64 572662306 to ptr), ptr inttoptr (i64 572662306 to ptr)], align 16
// PATTERN-O0: @__const.test_tailpad4_uninit.uninit = private unnamed_addr constant [4 x { i16, i8, [1 x i8] }] [{ i16, i8, [1 x i8] } { i16 [[I16]], i8 [[I8]], [1 x i8] c"\[[IC]]" }, { i16, i8, [1 x i8] } { i16 [[I16]], i8 [[I8]], [1 x i8] c"\[[IC]]" }, { i16, i8, [1 x i8] } { i16 [[I16]], i8 [[I8]], [1 x i8] c"\[[IC]]" }, { i16, i8, [1 x i8] } { i16 [[I16]], i8 [[I8]], [1 x i8] c"\[[IC]]" }], align
// PATTERN-O1-NOT: @__const.test_tailpad4_uninit.uninit
-// PATTERN: @__const.test_tailpad4_custom.custom = private unnamed_addr constant [4 x { i16, i8, [1 x i8] }] [{ i16, i8, [1 x i8] } { i16 257, i8 1, [1 x i8] zeroinitializer }, { i16, i8, [1 x i8] } { i16 257, i8 1, [1 x i8] zeroinitializer }, { i16, i8, [1 x i8] } { i16 257, i8 1, [1 x i8] zeroinitializer }, { i16, i8, [1 x i8] } { i16 257, i8 1, [1 x i8] zeroinitializer }], align
-// ZERO: @__const.test_tailpad4_custom.custom = private unnamed_addr constant [4 x { i16, i8, [1 x i8] }] [{ i16, i8, [1 x i8] } { i16 257, i8 1, [1 x i8] zeroinitializer }, { i16, i8, [1 x i8] } { i16 257, i8 1, [1 x i8] zeroinitializer }, { i16, i8, [1 x i8] } { i16 257, i8 1, [1 x i8] zeroinitializer }, { i16, i8, [1 x i8] } { i16 257, i8 1, [1 x i8] zeroinitializer }], align 16
struct tailpad { short s; char c; };
// PATTERN-O0: @__const.test_atomicnotlockfree_uninit.uninit = private unnamed_addr constant %struct.notlockfree { [4 x i64] {{\[}}i64 [[I64]], i64 [[I64]], i64 [[I64]], i64 [[I64]]] }, align
// PATTERN-O1-NOT: @__const.test_atomicnotlockfree_uninit.uninit
@@ -1503,7 +1499,11 @@ TEST_CUSTOM(unmatchedreverse, unmatchedreverse, { .c = 42 });
// CHECK-O0: call void @{{.*}}used{{.*}}%custom)
// PATTERN-O1: store i8 42, ptr {{.*}}, align 4
// PATTERN-O1-NEXT: %[[I:[^ ]*]] = getelementptr inbounds i8, ptr %custom, i64 1
-// PATTERN-O1-NEXT: call void @llvm.memset.{{.*}}({{.*}}, i8 -86, i64 3, {{.*}})
+// PATTERN-O1-NEXT: store i8 -86, ptr %[[I]], align {{.*}}
+// PATTERN-O1-NEXT: %[[I:[^ ]*]] = getelementptr inbounds i8, ptr %custom, i64 2
+// PATTERN-O1-NEXT: store i8 -86, ptr %[[I]], align {{.*}}
+// PATTERN-O1-NEXT: %[[I:[^ ]*]] = getelementptr inbounds i8, ptr %custom, i64 3
+// PATTERN-O1-NEXT: store i8 -86, ptr %[[I]], align {{.*}}
// ZERO-O1: store i8 42, ptr {{.*}}, align 4
// ZERO-O1-NEXT: %[[I:[^ ]*]] = getelementptr inbounds i8, ptr %custom, i64 1
// ZERO-O1-NEXT: call void @llvm.memset.{{.*}}({{.*}}, i8 0, i64 3, {{.*}})
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