91ef930526
When possible (e.g. internal linkage), strip preallocated attribute off parameters/arguments. This requires removing the "preallocated" operand bundle from the call site, replacing @llvm.call.preallocated.arg() with an alloca and a bitcast to i8*, and removing the @llvm.call.preallocated.setup(). Since @llvm.call.preallocated.arg() can be called multiple times with the same arg index, we create an alloca per arg index. We add a @llvm.stacksave() where the @llvm.call.preallocated.setup() was and a @llvm.stackrestore() after the preallocated call to prevent the stack from blowing up. This is valid because the argument would normally not exist on the stack after the call before the transformation. This does not currently handle all possible preallocated calls. We will need to figure out where to put @llvm.stackrestore() in the cases where there is no obvious place to put it, for example conditional preallocated calls, invokes. This sort of transformation may need to be moved to somewhere more accessible to accomodate similar transformations (like inlining) in the future. Reviewers: efriedma, hans Subscribers: hiraditya, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D80951
70 lines
1.9 KiB
LLVM
70 lines
1.9 KiB
LLVM
; RUN: opt < %s -globalopt -S | FileCheck %s
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declare token @llvm.call.preallocated.setup(i32)
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declare i8* @llvm.call.preallocated.arg(token, i32)
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define internal i32 @f(i32* %m) {
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; CHECK-LABEL: define internal fastcc i32 @f
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%v = load i32, i32* %m
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ret i32 %v
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}
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define internal x86_thiscallcc i32 @g(i32* %m) {
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; CHECK-LABEL: define internal fastcc i32 @g
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%v = load i32, i32* %m
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ret i32 %v
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}
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; Leave this one alone, because the user went out of their way to request this
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; convention.
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define internal coldcc i32 @h(i32* %m) {
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; CHECK-LABEL: define internal coldcc i32 @h
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%v = load i32, i32* %m
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ret i32 %v
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}
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define internal i32 @j(i32* %m) {
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; CHECK-LABEL: define internal i32 @j
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%v = load i32, i32* %m
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ret i32 %v
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}
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define internal i32 @inalloca(i32* inalloca %p) {
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; CHECK-LABEL: define internal fastcc i32 @inalloca(i32* %p)
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%rv = load i32, i32* %p
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ret i32 %rv
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}
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define internal i32 @preallocated(i32* preallocated(i32) %p) {
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; CHECK-LABEL: define internal fastcc i32 @preallocated(i32* %p)
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%rv = load i32, i32* %p
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ret i32 %rv
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}
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define void @call_things() {
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%m = alloca i32
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call i32 @f(i32* %m)
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call x86_thiscallcc i32 @g(i32* %m)
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call coldcc i32 @h(i32* %m)
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call i32 @j(i32* %m)
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%args = alloca inalloca i32
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call i32 @inalloca(i32* inalloca %args)
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%c = call token @llvm.call.preallocated.setup(i32 1)
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%N = call i8* @llvm.call.preallocated.arg(token %c, i32 0) preallocated(i32)
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%n = bitcast i8* %N to i32*
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call i32 @preallocated(i32* preallocated(i32) %n) ["preallocated"(token %c)]
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ret void
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}
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; CHECK-LABEL: define void @call_things()
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; CHECK: call fastcc i32 @f
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; CHECK: call fastcc i32 @g
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; CHECK: call coldcc i32 @h
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; CHECK: call i32 @j
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; CHECK: call fastcc i32 @inalloca(i32* %args)
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; CHECK-NOT: llvm.call.preallocated
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; CHECK: call fastcc i32 @preallocated(i32* %n)
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@llvm.used = appending global [1 x i8*] [
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i8* bitcast (i32(i32*)* @j to i8*)
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], section "llvm.metadata"
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