xref: /aosp_15_r20/external/llvm/test/CodeGen/X86/2009-05-23-dagcombine-shifts.ll (revision 9880d6810fe72a1726cb53787c6711e909410d58)
1*9880d681SAndroid Build Coastguard Worker; RUN: llc < %s | FileCheck %s
2*9880d681SAndroid Build Coastguard Worker
3*9880d681SAndroid Build Coastguard Worker; Check that the shr(shl X, 56), 48) is not mistakenly turned into
4*9880d681SAndroid Build Coastguard Worker; a shr (X, -8) that gets subsequently "optimized away" as undef
5*9880d681SAndroid Build Coastguard Worker; PR4254
6*9880d681SAndroid Build Coastguard Worker
7*9880d681SAndroid Build Coastguard Worker; after fixing PR24373
8*9880d681SAndroid Build Coastguard Worker; shlq $56, %rdi
9*9880d681SAndroid Build Coastguard Worker; sarq $48, %rdi
10*9880d681SAndroid Build Coastguard Worker; folds into
11*9880d681SAndroid Build Coastguard Worker; movsbq %dil, %rax
12*9880d681SAndroid Build Coastguard Worker; shlq $8, %rax
13*9880d681SAndroid Build Coastguard Worker; which is better for x86
14*9880d681SAndroid Build Coastguard Worker
15*9880d681SAndroid Build Coastguard Workertarget datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
16*9880d681SAndroid Build Coastguard Workertarget triple = "x86_64-unknown-linux-gnu"
17*9880d681SAndroid Build Coastguard Worker
18*9880d681SAndroid Build Coastguard Workerdefine i64 @foo(i64 %b) nounwind readnone {
19*9880d681SAndroid Build Coastguard Workerentry:
20*9880d681SAndroid Build Coastguard Worker; CHECK-LABEL: foo:
21*9880d681SAndroid Build Coastguard Worker; CHECK: movsbq %dil, %rax
22*9880d681SAndroid Build Coastguard Worker; CHECK: shlq $8, %rax
23*9880d681SAndroid Build Coastguard Worker; CHECK: orq $1, %rax
24*9880d681SAndroid Build Coastguard Worker	%shl = shl i64 %b, 56		; <i64> [#uses=1]
25*9880d681SAndroid Build Coastguard Worker	%shr = ashr i64 %shl, 48		; <i64> [#uses=1]
26*9880d681SAndroid Build Coastguard Worker	%add5 = or i64 %shr, 1		; <i64> [#uses=1]
27*9880d681SAndroid Build Coastguard Worker	ret i64 %add5
28*9880d681SAndroid Build Coastguard Worker}
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