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[AArch64] Don't promote constants with float ConstantExpr. 

Currently the AsmPrinter cannot emit some floating point constant
expressions in global initializers. Avoid generating them.

Reviewers: dmgreen, t.p.northover, arsenm, efriedma, Gerolf

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D79865
This commit is contained in:
Florian Hahn 2020-05-13 23:31:47 +01:00
parent bfa200ebcf
commit 824a859332
2 changed files with 82 additions and 3 deletions
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21
llvm/lib/Target/AArch64/AArch64PromoteConstant.cpp
View File

@ -250,6 +250,20 @@ static bool isConstantUsingVectorTy(const Type *CstTy) {
return false;
}
// Returns true if \p C contains only ConstantData leafs and no global values,
// block addresses or constant expressions. Traverses ConstantAggregates.
static bool containsOnlyConstantData(const Constant *C) {
if (isa<ConstantData>(C))
return true;
if (isa<GlobalValue>(C) || isa<BlockAddress>(C) || isa<ConstantExpr>(C))
return false;
return all_of(C->operands(), [](const Use &U) {
return containsOnlyConstantData(cast<Constant>(&U));
});
}
/// Check if the given use (Instruction + OpIdx) of Cst should be converted into
/// a load of a global variable initialized with Cst.
/// A use should be converted if it is legal to do so.
@ -550,9 +564,10 @@ bool AArch64PromoteConstant::runOnFunction(Function &F,
for (Use &U : I.operands()) {
Constant *Cst = dyn_cast<Constant>(U);
// There is no point in promoting global values as they are already
// global. Do not promote constant expressions either, as they may
// require some code expansion.
if (!Cst || isa<GlobalValue>(Cst) || isa<ConstantExpr>(Cst))
// global. Do not promote constants containing constant expression, global
// values or blockaddresses either, as they may require some code
// expansion.
if (!Cst || isa<GlobalValue>(Cst) || !containsOnlyConstantData(Cst))
continue;
// Check if this constant is worth promoting.

64
llvm/test/CodeGen/AArch64/arm64-promote-const-complex-initializers.ll Normal file
View File

@ -0,0 +1,64 @@
; RUN: llc -o - %s | FileCheck %s
; AsmPrinter cannot lower floating point constant expressions in global
; initializers. Check that we do not create new globals with float constant
; expressions in initializers.
target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
target triple = "arm64-apple-ios14.0.0"
define [1 x <4 x float>] @test1() {
; CHECK-LABEL: .p2align 4 ; -- Begin function test1
; CHECK-NEXT: lCPI0_0:
; CHECK-NEXT: .quad 0 ; 0x0
; CHECK-NEXT: .quad 4575657221408423936 ; 0x3f80000000000000
; CHECK-NEXT: .section __TEXT,__text,regular,pure_instructions
; CHECK-NEXT: .globl _test1
; CHECK-NEXT: .p2align 2
; CHECK-NEXT: _test1: ; @test1
; CHECK-NEXT: .cfi_startproc
; CHECK-NEXT: ; %bb.0:
; CHECK-NEXT: Lloh0:
; CHECK-NEXT: adrp x8, lCPI0_0@PAGE
; CHECK-NEXT: Lloh1:
; CHECK-NEXT: ldr q0, [x8, lCPI0_0@PAGEOFF]
; CHECK-NEXT: ret
ret [1 x <4 x float>] [<4 x float> bitcast (<1 x i128> <i128 84405977732342157929391748327801880576> to <4 x float>)]
}
define [1 x <4 x float>] @test2() {
; CHECK-LABEL: .p2align 4 ; -- Begin function test2
; CHECK-NEXT: lCPI1_0:
; CHECK-NEXT: .long 0x00000000 ; float 0
; CHECK-NEXT: .long 0x00000000 ; float 0
; CHECK-NEXT: .long 0x00000000 ; float 0
; CHECK-NEXT: .long 0x3f800000 ; float 1
; CHECK-NEXT: .section __TEXT,__text,regular,pure_instructions
; CHECK-NEXT: .globl _test2
; CHECK-NEXT: .p2align 2
; CHECK-NEXT: _test2: ; @test2
; CHECK-NEXT: .cfi_startproc
; CHECK-NEXT: ; %bb.0:
; CHECK-NEXT: Lloh2:
; CHECK-NEXT: adrp x8, lCPI1_0@PAGE
; CHECK-NEXT: Lloh3:
; CHECK-NEXT: ldr q1, [x8, lCPI1_0@PAGEOFF]
; CHECK-NEXT: mov s2, v1[1]
; CHECK-NEXT: fneg s0, s1
; CHECK-NEXT: mov s3, v1[2]
; CHECK-NEXT: fneg s2, s2
; CHECK-NEXT: mov s1, v1[3]
; CHECK-NEXT: fneg s3, s3
; CHECK-NEXT: mov.s v0[1], v2[0]
; CHECK-NEXT: mov.s v0[2], v3[0]
; CHECK-NEXT: fneg s1, s1
; CHECK-NEXT: mov.s v0[3], v1[0]
; CHECK-NEXT: ret
;
ret [1 x <4 x float>] [<4 x float>
<float fneg (float extractelement (<4 x float> bitcast (<1 x i128> <i128 84405977732342157929391748327801880576> to <4 x float>), i32 0)),
float fneg (float extractelement (<4 x float> bitcast (<1 x i128> <i128 84405977732342157929391748327801880576> to <4 x float>), i32 1)),
float fneg (float extractelement (<4 x float> bitcast (<1 x i128> <i128 84405977732342157929391748327801880576> to <4 x float>), i32 2)),
float fneg (float extractelement (<4 x float> bitcast (<1 x i128> <i128 84405977732342157929391748327801880576> to <4 x float>), i32 3))>]
}