[llvm] r280285 - [WebAssembly] Disable folding of GA+reg into load/store constant offsets
Derek Schuff via llvm-commits
llvm-commits at lists.llvm.org
Wed Aug 31 13:27:20 PDT 2016
Author: dschuff
Date: Wed Aug 31 15:27:20 2016
New Revision: 280285
URL: http://llvm.org/viewvc/llvm-project?rev=280285&view=rev
Log:
[WebAssembly] Disable folding of GA+reg into load/store constant offsets
Summary:
If the register has a negative value then unsigned overflow will occur;
this case is sometimes even created intentionally by LSR. For now
disable GA+reg folding. Fixes PR29127
Differential Revision: https://reviews.llvm.org/D24053
Added:
llvm/trunk/test/CodeGen/WebAssembly/negative-base-reg.ll
Modified:
llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrMemory.td
llvm/trunk/test/CodeGen/WebAssembly/address-offsets.ll
Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrMemory.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrMemory.td?rev=280285&r1=280284&r2=280285&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrMemory.td (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrMemory.td Wed Aug 31 15:27:20 2016
@@ -41,15 +41,13 @@ def or_is_add : PatFrag<(ops node:$lhs,
}]>;
// GlobalAddresses are conceptually unsigned values, so we can also fold them
-// into immediate values as long as their offsets are non-negative.
+// into immediate values as long as the add is 'nuw'.
+// TODO: We'd like to also match GA offsets but there are cases where the
+// register can have a negative value. Find out what more we can do.
def regPlusGA : PatFrag<(ops node:$addr, node:$off),
(add node:$addr, node:$off),
[{
- return N->getFlags()->hasNoUnsignedWrap() ||
- (N->getOperand(1)->getOpcode() == WebAssemblyISD::Wrapper &&
- isa<GlobalAddressSDNode>(N->getOperand(1)->getOperand(0)) &&
- cast<GlobalAddressSDNode>(N->getOperand(1)->getOperand(0))
- ->getOffset() >= 0);
+ return N->getFlags()->hasNoUnsignedWrap();
}]>;
// We don't need a regPlusES because external symbols never have constant
Modified: llvm/trunk/test/CodeGen/WebAssembly/address-offsets.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/address-offsets.ll?rev=280285&r1=280284&r2=280285&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/address-offsets.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/address-offsets.ll Wed Aug 31 15:27:20 2016
@@ -28,13 +28,17 @@ define i32 @load_test0_noinbounds() {
ret i32 %t
}
+; TODO: load_test1 - load_test8 are disabled because folding GA+reg is disabled
+; (there are cases where the value in the reg can be negative).
+; Likewise for stores.
+
; CHECK-LABEL: load_test1:
; CHECK-NEXT: param i32{{$}}
; CHECK-NEXT: result i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
-; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.load $push2=, g+40($pop1){{$}}
-; CHECK-NEXT: return $pop2{{$}}
+; CHECK-NEX T: i32.shl $push1=, $0, $pop0{{$}}
+; CHECK-NEX T: i32.load $push2=, g+40($pop1){{$}}
+; CHECK-NEX T: return $pop2{{$}}
define i32 @load_test1(i32 %n) {
%add = add nsw i32 %n, 10
%arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %add
@@ -46,9 +50,9 @@ define i32 @load_test1(i32 %n) {
; CHECK-NEXT: param i32{{$}}
; CHECK-NEXT: result i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
-; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.load $push2=, g+40($pop1){{$}}
-; CHECK-NEXT: return $pop2{{$}}
+; CHECK-NEX T: i32.shl $push1=, $0, $pop0{{$}}
+; CHECK-NEX T: i32.load $push2=, g+40($pop1){{$}}
+; CHECK-NEX T: return $pop2{{$}}
define i32 @load_test2(i32 %n) {
%add = add nsw i32 10, %n
%arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %add
@@ -60,9 +64,9 @@ define i32 @load_test2(i32 %n) {
; CHECK-NEXT: param i32{{$}}
; CHECK-NEXT: result i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
-; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.load $push2=, g+40($pop1){{$}}
-; CHECK-NEXT: return $pop2{{$}}
+; CHECK-NEX T: i32.shl $push1=, $0, $pop0{{$}}
+; CHECK-NEX T: i32.load $push2=, g+40($pop1){{$}}
+; CHECK-NEX T: return $pop2{{$}}
define i32 @load_test3(i32 %n) {
%add.ptr = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %n
%add.ptr1 = getelementptr inbounds i32, i32* %add.ptr, i32 10
@@ -74,9 +78,9 @@ define i32 @load_test3(i32 %n) {
; CHECK-NEXT: param i32{{$}}
; CHECK-NEXT: result i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
-; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.load $push2=, g+40($pop1){{$}}
-; CHECK-NEXT: return $pop2{{$}}
+; CHECK-NEX T: i32.shl $push1=, $0, $pop0{{$}}
+; CHECK-NEX T: i32.load $push2=, g+40($pop1){{$}}
+; CHECK-NEX T: return $pop2{{$}}
define i32 @load_test4(i32 %n) {
%add.ptr = getelementptr inbounds i32, i32* getelementptr inbounds ([0 x i32], [0 x i32]* @g, i32 0, i32 10), i32 %n
%t = load i32, i32* %add.ptr, align 4
@@ -87,9 +91,9 @@ define i32 @load_test4(i32 %n) {
; CHECK-NEXT: param i32{{$}}
; CHECK-NEXT: result i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
-; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.load $push2=, g+40($pop1){{$}}
-; CHECK-NEXT: return $pop2{{$}}
+; CHECK-NEX T: i32.shl $push1=, $0, $pop0{{$}}
+; CHECK-NEX T: i32.load $push2=, g+40($pop1){{$}}
+; CHECK-NEX T: return $pop2{{$}}
define i32 @load_test5(i32 %n) {
%add.ptr = getelementptr inbounds i32, i32* getelementptr inbounds ([0 x i32], [0 x i32]* @g, i32 0, i32 10), i32 %n
%t = load i32, i32* %add.ptr, align 4
@@ -100,9 +104,9 @@ define i32 @load_test5(i32 %n) {
; CHECK-NEXT: param i32{{$}}
; CHECK-NEXT: result i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
-; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.load $push2=, g+40($pop1){{$}}
-; CHECK-NEXT: return $pop2{{$}}
+; CHECK-NEX T: i32.shl $push1=, $0, $pop0{{$}}
+; CHECK-NEX T: i32.load $push2=, g+40($pop1){{$}}
+; CHECK-NEX T: return $pop2{{$}}
define i32 @load_test6(i32 %n) {
%add = add nsw i32 %n, 10
%add.ptr = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %add
@@ -114,9 +118,9 @@ define i32 @load_test6(i32 %n) {
; CHECK-NEXT: param i32{{$}}
; CHECK-NEXT: result i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
-; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.load $push2=, g+40($pop1){{$}}
-; CHECK-NEXT: return $pop2{{$}}
+; CHECK-NEX T: i32.shl $push1=, $0, $pop0{{$}}
+; CHECK-NEX T: i32.load $push2=, g+40($pop1){{$}}
+; CHECK-NEX T: return $pop2{{$}}
define i32 @load_test7(i32 %n) {
%add.ptr = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %n
%add.ptr1 = getelementptr inbounds i32, i32* %add.ptr, i32 10
@@ -128,9 +132,9 @@ define i32 @load_test7(i32 %n) {
; CHECK-NEXT: param i32{{$}}
; CHECK-NEXT: result i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
-; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.load $push2=, g+40($pop1){{$}}
-; CHECK-NEXT: return $pop2{{$}}
+; CHECK-NEX T: i32.shl $push1=, $0, $pop0{{$}}
+; CHECK-NEX T: i32.load $push2=, g+40($pop1){{$}}
+; CHECK-NEX T: return $pop2{{$}}
define i32 @load_test8(i32 %n) {
%add = add nsw i32 10, %n
%add.ptr = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %add
@@ -374,8 +378,8 @@ define void @store_test0_noinbounds(i32
; CHECK-NEXT: param i32, i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.store $drop=, g+40($pop1), $1{{$}}
-; CHECK-NEXT: return{{$}}
+; CHECK-NEX T: i32.store $drop=, g+40($pop1), $1{{$}}
+; CHECK-NEX T: return{{$}}
define void @store_test1(i32 %n, i32 %i) {
%add = add nsw i32 %n, 10
%arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %add
@@ -387,8 +391,8 @@ define void @store_test1(i32 %n, i32 %i)
; CHECK-NEXT: param i32, i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.store $drop=, g+40($pop1), $1{{$}}
-; CHECK-NEXT: return{{$}}
+; CHECK-NEX T: i32.store $drop=, g+40($pop1), $1{{$}}
+; CHECK-NEX T: return{{$}}
define void @store_test2(i32 %n, i32 %i) {
%add = add nsw i32 10, %n
%arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %add
@@ -400,8 +404,8 @@ define void @store_test2(i32 %n, i32 %i)
; CHECK-NEXT: param i32, i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.store $drop=, g+40($pop1), $1{{$}}
-; CHECK-NEXT: return{{$}}
+; CHECK-NEX T: i32.store $drop=, g+40($pop1), $1{{$}}
+; CHECK-NEX T: return{{$}}
define void @store_test3(i32 %n, i32 %i) {
%add.ptr = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %n
%add.ptr1 = getelementptr inbounds i32, i32* %add.ptr, i32 10
@@ -413,8 +417,8 @@ define void @store_test3(i32 %n, i32 %i)
; CHECK-NEXT: param i32, i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.store $drop=, g+40($pop1), $1{{$}}
-; CHECK-NEXT: return{{$}}
+; CHECK-NEX T: i32.store $drop=, g+40($pop1), $1{{$}}
+; CHECK-NEX T: return{{$}}
define void @store_test4(i32 %n, i32 %i) {
%add.ptr = getelementptr inbounds i32, i32* getelementptr inbounds ([0 x i32], [0 x i32]* @g, i32 0, i32 10), i32 %n
store i32 %i, i32* %add.ptr, align 4
@@ -425,8 +429,8 @@ define void @store_test4(i32 %n, i32 %i)
; CHECK-NEXT: param i32, i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.store $drop=, g+40($pop1), $1{{$}}
-; CHECK-NEXT: return{{$}}
+; CHECK-NEX T: i32.store $drop=, g+40($pop1), $1{{$}}
+; CHECK-NEX T: return{{$}}
define void @store_test5(i32 %n, i32 %i) {
%add.ptr = getelementptr inbounds i32, i32* getelementptr inbounds ([0 x i32], [0 x i32]* @g, i32 0, i32 10), i32 %n
store i32 %i, i32* %add.ptr, align 4
@@ -437,8 +441,8 @@ define void @store_test5(i32 %n, i32 %i)
; CHECK-NEXT: param i32, i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.store $drop=, g+40($pop1), $1{{$}}
-; CHECK-NEXT: return{{$}}
+; CHECK-NEX T: i32.store $drop=, g+40($pop1), $1{{$}}
+; CHECK-NEX T: return{{$}}
define void @store_test6(i32 %n, i32 %i) {
%add = add nsw i32 %n, 10
%add.ptr = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %add
@@ -450,8 +454,8 @@ define void @store_test6(i32 %n, i32 %i)
; CHECK-NEXT: param i32, i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.store $drop=, g+40($pop1), $1{{$}}
-; CHECK-NEXT: return{{$}}
+; CHECK-NEX T: i32.store $drop=, g+40($pop1), $1{{$}}
+; CHECK-NEX T: return{{$}}
define void @store_test7(i32 %n, i32 %i) {
%add.ptr = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %n
%add.ptr1 = getelementptr inbounds i32, i32* %add.ptr, i32 10
@@ -463,8 +467,8 @@ define void @store_test7(i32 %n, i32 %i)
; CHECK-NEXT: param i32, i32{{$}}
; CHECK-NEXT: i32.const $push0=, 2{{$}}
; CHECK-NEXT: i32.shl $push1=, $0, $pop0{{$}}
-; CHECK-NEXT: i32.store $drop=, g+40($pop1), $1{{$}}
-; CHECK-NEXT: return{{$}}
+; CHECK-NEX T: i32.store $drop=, g+40($pop1), $1{{$}}
+; CHECK-NEX T: return{{$}}
define void @store_test8(i32 %n, i32 %i) {
%add = add nsw i32 10, %n
%add.ptr = getelementptr inbounds [0 x i32], [0 x i32]* @g, i32 0, i32 %add
Added: llvm/trunk/test/CodeGen/WebAssembly/negative-base-reg.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/negative-base-reg.ll?rev=280285&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/negative-base-reg.ll (added)
+++ llvm/trunk/test/CodeGen/WebAssembly/negative-base-reg.ll Wed Aug 31 15:27:20 2016
@@ -0,0 +1,43 @@
+; RUN: llc < %s -asm-verbose=false -verify-machineinstrs -disable-wasm-fallthrough-return-opt | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32"
+
+ at args = hidden local_unnamed_addr global [32 x i32] zeroinitializer, align 16
+
+; Function Attrs: norecurse nounwind
+define hidden i32 @main() local_unnamed_addr #0 {
+
+; If LSR stops selecting a negative base reg value, then this test will no
+; longer be useful as written.
+; CHECK: i32.const $0=, -128
+entry:
+ br label %for.body
+
+for.body: ; preds = %for.body, %entry
+ %i.04 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+; The offset should not be folded into the store.
+; CHECK: i32.const $push{{[0-9]+}}=, args+128
+; CHECK: i32.add
+; CHECK: i32.store $drop=, 0(
+ %arrayidx = getelementptr inbounds [32 x i32], [32 x i32]* @args, i32 0, i32 %i.04
+ store i32 1, i32* %arrayidx, align 4, !tbaa !1
+ %inc = add nuw nsw i32 %i.04, 1
+ %exitcond = icmp eq i32 %inc, 32
+ br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !5
+
+for.end: ; preds = %for.body
+ ret i32 0
+}
+
+attributes #0 = { norecurse nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="generic" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.ident = !{!0}
+
+!0 = !{!"clang version 4.0.0 (trunk 279056) (llvm/trunk 279074)"}
+!1 = !{!2, !2, i64 0}
+!2 = !{!"int", !3, i64 0}
+!3 = !{!"omnipotent char", !4, i64 0}
+!4 = !{!"Simple C/C++ TBAA"}
+!5 = distinct !{!5, !6}
+!6 = !{!"llvm.loop.unroll.disable"}
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