mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-23 11:13:28 +01:00
f65b040dae
Summary:
When moving add and sub to memory operand instructions,
aarch64-ldst-opt would prematurally pop the stack pointer,
before memory instructions that do access the stack using
indirect loads.
e.g.
```
int foo(int offset){
int local[4] = {0};
return local[offset];
}
```
would generate:
```
sub sp, sp, #16 ; Push the stack
mov x8, sp ; Save stack in register
stp xzr, xzr, [sp], #16 ; Zero initialize stack, and post-increment, making it invalid
------ If an exception goes here, the stack value might be corrupted
ldr w0, [x8, w0, sxtw #2] ; Access correct position, but it is not guarded by SP
```
Reviewers: fhahn, foad, thegameg, eli.friedman, efriedma
Reviewed By: efriedma
Subscribers: efriedma, kristof.beyls, hiraditya, danielkiss, llvm-commits, simon_tatham
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D75755
97 lines
3.2 KiB
LLVM
97 lines
3.2 KiB
LLVM
; FIXME: Add tests for global-isel/fast-isel.
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; RUN: llc < %s -mtriple=arm64-windows | FileCheck %s
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; Returns <= 8 bytes should be in X0.
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%struct.S1 = type { i32, i32 }
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define dso_local i64 @"?f1"() {
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entry:
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; CHECK-LABEL: f1
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; CHECK: str xzr, [sp, #8]
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; CHECK: mov x0, xzr
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%retval = alloca %struct.S1, align 4
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%a = getelementptr inbounds %struct.S1, %struct.S1* %retval, i32 0, i32 0
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store i32 0, i32* %a, align 4
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%b = getelementptr inbounds %struct.S1, %struct.S1* %retval, i32 0, i32 1
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store i32 0, i32* %b, align 4
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%0 = bitcast %struct.S1* %retval to i64*
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%1 = load i64, i64* %0, align 4
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ret i64 %1
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}
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; Returns <= 16 bytes should be in X0/X1.
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%struct.S2 = type { i32, i32, i32, i32 }
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define dso_local [2 x i64] @"?f2"() {
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entry:
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; FIXME: Missed optimization, the entire SP push/pop could be removed
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; CHECK-LABEL: f2
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; CHECK: stp xzr, xzr, [sp, #-16]!
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; CHECK-NEXT: mov x0, xzr
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; CHECK-NEXT: mov x1, xzr
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; CHECK-NEXT: add sp, sp, #16
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%retval = alloca %struct.S2, align 4
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%a = getelementptr inbounds %struct.S2, %struct.S2* %retval, i32 0, i32 0
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store i32 0, i32* %a, align 4
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%b = getelementptr inbounds %struct.S2, %struct.S2* %retval, i32 0, i32 1
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store i32 0, i32* %b, align 4
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%c = getelementptr inbounds %struct.S2, %struct.S2* %retval, i32 0, i32 2
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store i32 0, i32* %c, align 4
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%d = getelementptr inbounds %struct.S2, %struct.S2* %retval, i32 0, i32 3
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store i32 0, i32* %d, align 4
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%0 = bitcast %struct.S2* %retval to [2 x i64]*
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%1 = load [2 x i64], [2 x i64]* %0, align 4
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ret [2 x i64] %1
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}
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; Arguments > 16 bytes should be passed in X8.
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%struct.S3 = type { i32, i32, i32, i32, i32 }
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define dso_local void @"?f3"(%struct.S3* noalias sret %agg.result) {
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entry:
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; CHECK-LABEL: f3
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; CHECK: stp xzr, xzr, [x8]
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; CHECK: str wzr, [x8, #16]
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%a = getelementptr inbounds %struct.S3, %struct.S3* %agg.result, i32 0, i32 0
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store i32 0, i32* %a, align 4
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%b = getelementptr inbounds %struct.S3, %struct.S3* %agg.result, i32 0, i32 1
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store i32 0, i32* %b, align 4
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%c = getelementptr inbounds %struct.S3, %struct.S3* %agg.result, i32 0, i32 2
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store i32 0, i32* %c, align 4
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%d = getelementptr inbounds %struct.S3, %struct.S3* %agg.result, i32 0, i32 3
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store i32 0, i32* %d, align 4
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%e = getelementptr inbounds %struct.S3, %struct.S3* %agg.result, i32 0, i32 4
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store i32 0, i32* %e, align 4
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ret void
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}
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; InReg arguments to non-instance methods must be passed in X0 and returns in
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; X0.
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%class.B = type { i32 }
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define dso_local void @"?f4"(%class.B* inreg noalias nocapture sret %agg.result) {
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entry:
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; CHECK-LABEL: f4
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; CHECK: mov w8, #1
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; CHECK: str w8, [x0]
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%X.i = getelementptr inbounds %class.B, %class.B* %agg.result, i64 0, i32 0
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store i32 1, i32* %X.i, align 4
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ret void
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}
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; InReg arguments to instance methods must be passed in X1 and returns in X0.
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%class.C = type { i8 }
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%class.A = type { i8 }
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define dso_local void @"?inst@C"(%class.C* %this, %class.A* inreg noalias sret %agg.result) {
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entry:
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; CHECK-LABEL: inst@C
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; CHECK: str x0, [sp, #8]
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; CHECK: mov x0, x1
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%this.addr = alloca %class.C*, align 8
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store %class.C* %this, %class.C** %this.addr, align 8
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%this1 = load %class.C*, %class.C** %this.addr, align 8
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ret void
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}
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