maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[PowerPC] Fix the check for 16-bit signed field in peephole 

When a D-Form instruction is fed by an add-immediate, we attempt
to merge the two immediates to form a single displacement so we
can remove the add-immediate.

However, we don't check whether the new displacement fits into
a 16-bit signed immediate field early enough. Namely, we do a
sign-extend from 16 bits first which will discard high bits and
then we check whether the result is a 16-bit signed immediate.
It of course will always be.

Move the check prior to the sign extend to ensure we are checking
the correct value.

Fixes https://bugs.llvm.org/show_bug.cgi?id=49640
This commit is contained in:
Nemanja Ivanovic 2021-03-19 06:24:42 -05:00
parent 4f750f6ebc
commit a8697c57fa
2 changed files with 72 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
View File

@ -4416,21 +4416,17 @@ bool PPCInstrInfo::isImmElgibleForForwarding(const MachineOperand &ImmMO,
// Sign-extend to 64-bits.
// DefMI may be folded with another imm form instruction, the result Imm is
// the sum of Imm of DefMI and BaseImm which is from imm form instruction.
APInt ActualValue(64, ImmMO.getImm() + BaseImm, true);
if (III.SignedImm && !ActualValue.isSignedIntN(III.ImmWidth))
return false;
if (!III.SignedImm && !ActualValue.isIntN(III.ImmWidth))
return false;
Imm = SignExtend64<16>(ImmMO.getImm() + BaseImm);
if (Imm % III.ImmMustBeMultipleOf)
return false;
if (III.TruncateImmTo)
Imm &= ((1 << III.TruncateImmTo) - 1);
if (III.SignedImm) {
APInt ActualValue(64, Imm, true);
if (!ActualValue.isSignedIntN(III.ImmWidth))
return false;
} else {
uint64_t UnsignedMax = (1 << III.ImmWidth) - 1;
if ((uint64_t)Imm > UnsignedMax)
return false;
}
}
else
return false;

67
llvm/test/CodeGen/PowerPC/out-of-range-dform.ll Normal file
View File

@ -0,0 +1,67 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mcpu=pwr9 -ppc-asm-full-reg-names -ppc-vsr-nums-as-vr \
; RUN: -mtriple=powerpc64le-unknown-unknown < %s | FileCheck %s \
; RUN: -check-prefix=CHECK-P9
@_ZL3num = external dso_local unnamed_addr global float, align 4
define dso_local void @main() local_unnamed_addr personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
; CHECK-P9-LABEL: main:
; CHECK-P9: # %bb.0: # %bb
; CHECK-P9-NEXT: mflr r0
; CHECK-P9-NEXT: std r0, 16(r1)
; CHECK-P9-NEXT: stdu r1, -32(r1)
; CHECK-P9-NEXT: .cfi_def_cfa_offset 32
; CHECK-P9-NEXT: .cfi_offset lr, 16
; CHECK-P9-NEXT: bl malloc
; CHECK-P9-NEXT: nop
; CHECK-P9-NEXT: addis r4, r2, _ZL3num@toc@ha
; CHECK-P9-NEXT: addi r3, r3, -25400
; CHECK-P9-NEXT: lfs f0, _ZL3num@toc@l(r4)
; CHECK-P9-NEXT: addis r4, r2, .LCPI0_0@toc@ha
; CHECK-P9-NEXT: lfs f1, .LCPI0_0@toc@l(r4)
; CHECK-P9-NEXT: li r4, 0
; CHECK-P9-NEXT: xsmulsp f0, f0, f1
; CHECK-P9-NEXT: cmpldi r4, 0
; CHECK-P9-NEXT: beq- cr0, .LBB0_2
; CHECK-P9-NEXT: .p2align 5
; CHECK-P9-NEXT: .LBB0_1: # %bb5
; CHECK-P9-NEXT: #
; CHECK-P9-NEXT: addi r3, r3, 25400
; CHECK-P9-NEXT: addi r4, r4, 25400
; CHECK-P9-NEXT: stfs f0, 15240(r3)
; CHECK-P9-NEXT: cmpldi r4, 0
; CHECK-P9-NEXT: bne+ cr0, .LBB0_1
; CHECK-P9-NEXT: .LBB0_2: # %bb16
bb:
%i = tail call noalias dereferenceable_or_null(6451600) i8* @malloc()
%i1 = bitcast i8* %i to float*
br label %bb2
bb2: ; preds = %bb5, %bb
%i3 = phi i64 [ 0, %bb ], [ %i15, %bb5 ]
%i4 = icmp eq i64 %i3, 0
br i1 %i4, label %bb16, label %bb5
bb5: ; preds = %bb2
%i6 = mul nuw nsw i64 %i3, 1270
%i7 = add nuw nsw i64 %i6, 0
%i8 = getelementptr inbounds float, float* %i1, i64 %i7
store float undef, float* %i8, align 4
%i9 = add nuw nsw i64 %i3, 3
%i10 = load float, float* @_ZL3num, align 4
%i11 = fmul float %i10, 0x3E00000000000000
%i12 = mul nuw nsw i64 %i9, 1270
%i13 = add nuw nsw i64 %i12, 0
%i14 = getelementptr inbounds float, float* %i1, i64 %i13
store float %i11, float* %i14, align 4
%i15 = add nuw nsw i64 %i3, 5
br label %bb2
bb16: ; preds = %bb2
unreachable
}
declare i32 @__gxx_personality_v0(...)
declare i8* @malloc() local_unnamed_addr