Hans Wennborg f4615feaa1 Revert "[DAG] Extend SearchForAndLoads with any_extend handling"
This caused builds to fail with

  llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:5638:
  bool (anonymous namespace)::DAGCombiner::BackwardsPropagateMask(llvm::SDNode *):
  Assertion `NewLoad && "Shouldn't be masking the load if it can't be narrowed"' failed.

See the code review for a link to a reproducer.

> This extends the code in SearchForAndLoads to be able to look through
> ANY_EXTEND nodes, which can be created from mismatching IR types where
> the AND node we begin from only demands the low parts of the register.
> That turns zext and sext into any_extends as only the low bits are
> demanded. To be able to look through ANY_EXTEND nodes we need to handle
> mismatching types in a few places, potentially truncating the mask to
> the size of the final load.
>
> Differential Revision: https://reviews.llvm.org/D117457

This reverts commit 578008789fd061a88ce47dac6ff627001b404348.
2022-01-18 10:50:55 +01:00

45 lines
1.6 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mtriple=x86_64-unknown-linux-gnu %s -o - | FileCheck %s
@ll = dso_local local_unnamed_addr global i64 0, align 8
@x = dso_local local_unnamed_addr global i64 2651237805702985558, align 8
@s1 = dso_local local_unnamed_addr global { i8, i8 } { i8 123, i8 5 }, align 2
@s2 = dso_local local_unnamed_addr global { i8, i8 } { i8 -122, i8 3 }, align 2
define dso_local void @PR35765() {
; CHECK-LABEL: PR35765:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: movb s1(%rip), %cl
; CHECK-NEXT: addb $-118, %cl
; CHECK-NEXT: movl $4, %eax
; CHECK-NEXT: shll %cl, %eax
; CHECK-NEXT: movzwl x(%rip), %ecx
; CHECK-NEXT: movzwl s2(%rip), %edx
; CHECK-NEXT: notl %edx
; CHECK-NEXT: orl $63488, %edx # imm = 0xF800
; CHECK-NEXT: movzwl %dx, %edx
; CHECK-NEXT: orl %ecx, %edx
; CHECK-NEXT: xorl %eax, %edx
; CHECK-NEXT: movslq %edx, %rax
; CHECK-NEXT: movq %rax, ll(%rip)
; CHECK-NEXT: retq
entry:
%bf.load.i = load i16, i16* bitcast ({ i8, i8 }* @s1 to i16*), align 2
%bf.clear.i = and i16 %bf.load.i, 2047
%conv.i = zext i16 %bf.clear.i to i32
%sub.i = add nsw i32 %conv.i, -1398
%shl.i = shl i32 4, %sub.i
%0 = load i64, i64* @x, align 8
%bf.load1.i = load i16, i16* bitcast ({ i8, i8 }* @s2 to i16*), align 2
%bf.clear2.i = and i16 %bf.load1.i, 2047
%1 = xor i16 %bf.clear2.i, -1
%neg.i = zext i16 %1 to i64
%or.i = or i64 %0, %neg.i
%conv5.i = trunc i64 %or.i to i32
%conv6.i = and i32 %conv5.i, 65535
%xor.i = xor i32 %conv6.i, %shl.i
%conv7.i = sext i32 %xor.i to i64
store i64 %conv7.i, i64* @ll, align 8
ret void
}