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clang-p2996/llvm/test/Transforms/InstSimplify/ConstProp/loads.ll
Björn Pettersson 7677453886 [ConstantFolding] Do not consider padded-in-memory types as uniform (#81854) 
Teaching ConstantFoldLoadFromUniformValue that types that are padded in
memory can't be considered as uniform.

Using the big hammer to prevent optimizations when loading from a
constant for which DataLayout::typeSizeEqualsStoreSize would return
false.

Main problem solved would be something like this:
  store i17 -1, ptr %p, align 4
  %v = load i8, ptr %p, align 1
If for example the i17 occupies 32 bits in memory, then LLVM IR doesn't
really tell where the padding goes. And even if we assume that the 15
most significant bits are padding, then they should be considered as
undefined (even if LLVM backend typically would pad with zeroes).
Anyway, for a big-endian target the load would read those most
significant bits, which aren't guaranteed to be one's. So it would be
wrong to constant fold the load as returning -1.

If LLVM IR had been more explicit about the placement of padding, then
we could allow the constant fold of the load in the example, but only
for little-endian.

Fixes: https://github.com/llvm/llvm-project/issues/81793
2024-02-15 15:40:21 +01:00

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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -data-layout="e-p:64:64:64-p1:16:16:16-p2:64:64:64-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-s0:64:64-ni:2" -passes=instsimplify -S | FileCheck %s --check-prefixes=CHECK,LE
; RUN: opt < %s -data-layout="E-p:64:64:64-p1:16:16:16-p2:64:64:64-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-s0:64:64-ni:2" -passes=instsimplify -S | FileCheck %s --check-prefixes=CHECK,BE
; {{ 0xDEADBEEF, 0xBA }, 0xCAFEBABE}
@g1 = constant {{i32,i8},i32} {{i32,i8} { i32 -559038737, i8 186 }, i32 -889275714 }
@g2 = constant double 1.0
; { 0x7B, 0x06B1BFF8 }
@g3 = constant {i64, i64} { i64 123, i64 112312312 }
; Simple load
define i32 @test1() {
; CHECK-LABEL: @test1(
; CHECK-NEXT: ret i32 -559038737
;
%r = load i32, ptr getelementptr ({{i32,i8},i32}, ptr @g1, i32 0, i32 0, i32 0)
ret i32 %r
}
; PR3152
; Load of first 16 bits of 32-bit value.
define i16 @test2() {
; LE-LABEL: @test2(
; LE-NEXT: ret i16 -16657
;
; BE-LABEL: @test2(
; BE-NEXT: ret i16 -8531
;
%r = load i16, ptr getelementptr ({{i32,i8},i32}, ptr @g1, i32 0, i32 0, i32 0)
ret i16 %r
}
define i16 @test2_addrspacecast() {
; LE-LABEL: @test2_addrspacecast(
; LE-NEXT: ret i16 -16657
;
; BE-LABEL: @test2_addrspacecast(
; BE-NEXT: ret i16 -8531
;
%r = load i16, ptr addrspace(1) addrspacecast(ptr getelementptr ({{i32,i8},i32}, ptr @g1, i32 0, i32 0, i32 0) to ptr addrspace(1))
ret i16 %r
}
; Load of second 16 bits of 32-bit value.
define i16 @test3() {
; LE-LABEL: @test3(
; LE-NEXT: ret i16 -8531
;
; BE-LABEL: @test3(
; BE-NEXT: ret i16 -16657
;
%r = load i16, ptr getelementptr(i16, ptr getelementptr ({{i32,i8},i32}, ptr @g1, i32 0, i32 0, i32 0), i32 1)
ret i16 %r
}
; Load of 8 bit field + tail padding.
define i16 @test4() {
; LE-LABEL: @test4(
; LE-NEXT: ret i16 186
;
; BE-LABEL: @test4(
; BE-NEXT: ret i16 -17920
;
%r = load i16, ptr getelementptr(i16, ptr getelementptr ({{i32,i8},i32}, ptr @g1, i32 0, i32 0, i32 0), i32 2)
ret i16 %r
}
; Load of double bits.
define i64 @test6() {
; CHECK-LABEL: @test6(
; CHECK-NEXT: ret i64 4607182418800017408
;
%r = load i64, ptr @g2
ret i64 %r
}
; Load of double bits.
define i16 @test7() {
; LE-LABEL: @test7(
; LE-NEXT: ret i16 0
;
; BE-LABEL: @test7(
; BE-NEXT: ret i16 16368
;
%r = load i16, ptr @g2
ret i16 %r
}
; Double load.
define double @test8() {
; LE-LABEL: @test8(
; LE-NEXT: ret double 0xBADEADBEEF
;
; BE-LABEL: @test8(
; BE-NEXT: ret double 0xDEADBEEFBA000000
;
%r = load double, ptr @g1
ret double %r
}
; i128 load.
define i128 @test_i128() {
; LE-LABEL: @test_i128(
; LE-NEXT: ret i128 2071796475790618158476296315
;
; BE-LABEL: @test_i128(
; BE-NEXT: ret i128 2268949521066387161080
;
%r = load i128, ptr @g3
ret i128 %r
}
define fp128 @test_fp128() {
; LE-LABEL: @test_fp128(
; LE-NEXT: ret fp128 0xL000000000000007B0000000006B1BFF8
;
; BE-LABEL: @test_fp128(
; BE-NEXT: ret fp128 0xL0000000006B1BFF8000000000000007B
;
%r = load fp128, ptr @g3
ret fp128 %r
}
define ppc_fp128 @test_ppc_fp128() {
; LE-LABEL: @test_ppc_fp128(
; LE-NEXT: ret ppc_fp128 bitcast (i128 2071796475790618158476296315 to ppc_fp128)
;
; BE-LABEL: @test_ppc_fp128(
; BE-NEXT: ret ppc_fp128 bitcast (i128 2268949521066387161080 to ppc_fp128)
;
%r = load ppc_fp128, ptr @g3
ret ppc_fp128 %r
}
define x86_fp80 @test_x86_fp80() {
; LE-LABEL: @test_x86_fp80(
; LE-NEXT: ret x86_fp80 0xKFFFF000000000000007B
;
; BE-LABEL: @test_x86_fp80(
; BE-NEXT: ret x86_fp80 0xK000000000000007B0000
;
%r = load x86_fp80, ptr @g3
ret x86_fp80 %r
}
define bfloat @test_bfloat() {
; LE-LABEL: @test_bfloat(
; LE-NEXT: ret bfloat 0xR007B
;
; BE-LABEL: @test_bfloat(
; BE-NEXT: ret bfloat 0xR0000
;
%r = load bfloat, ptr @g3
ret bfloat %r
}
; vector load.
define <2 x i64> @test10() {
; CHECK-LABEL: @test10(
; CHECK-NEXT: ret <2 x i64> <i64 123, i64 112312312>
;
%r = load <2 x i64>, ptr @g3
ret <2 x i64> %r
}
; PR5287
; { 0xA1, 0x08 }
@g4 = internal constant { i8, i8 } { i8 -95, i8 8 }
define i16 @test11() nounwind {
; LE-LABEL: @test11(
; LE-NEXT: entry:
; LE-NEXT: ret i16 2209
;
; BE-LABEL: @test11(
; BE-NEXT: entry:
; BE-NEXT: ret i16 -24312
;
entry:
%a = load i16, ptr @g4
ret i16 %a
}
; PR5551
@test12g = private constant [6 x i8] c"a\00b\00\00\00"
define i16 @test12() {
; LE-LABEL: @test12(
; LE-NEXT: ret i16 98
;
; BE-LABEL: @test12(
; BE-NEXT: ret i16 25088
;
%a = load i16, ptr getelementptr inbounds ([3 x i16], ptr @test12g, i32 0, i64 1)
ret i16 %a
}
; PR5978
@g5 = constant i8 4
define i1 @test13() {
; CHECK-LABEL: @test13(
; CHECK-NEXT: ret i1 false
;
%A = load i1, ptr @g5
ret i1 %A
}
@g6 = constant [2 x ptr] [ptr inttoptr (i64 1 to ptr), ptr inttoptr (i64 2 to ptr)]
define i64 @test14() nounwind {
; CHECK-LABEL: @test14(
; CHECK-NEXT: entry:
; CHECK-NEXT: ret i64 1
;
entry:
%tmp = load i64, ptr @g6
ret i64 %tmp
}
; Check with address space pointers
@g6_as1 = constant [2 x ptr addrspace(1)] [ptr addrspace(1) inttoptr (i16 1 to ptr addrspace(1)), ptr addrspace(1) inttoptr (i16 2 to ptr addrspace(1))]
define i16 @test14_as1() nounwind {
; CHECK-LABEL: @test14_as1(
; CHECK-NEXT: entry:
; CHECK-NEXT: ret i16 1
;
entry:
%tmp = load i16, ptr @g6_as1
ret i16 %tmp
}
define i64 @test15() nounwind {
; CHECK-LABEL: @test15(
; CHECK-NEXT: entry:
; CHECK-NEXT: ret i64 2
;
entry:
%tmp = load i64, ptr getelementptr inbounds ([2 x ptr], ptr @g6, i32 0, i64 1)
ret i64 %tmp
}
@gv7 = constant [4 x ptr] [ptr null, ptr inttoptr (i64 -14 to ptr), ptr null, ptr null]
define i64 @test16.1() {
; CHECK-LABEL: @test16.1(
; CHECK-NEXT: ret i64 0
;
%v = load i64, ptr @gv7, align 8
ret i64 %v
}
define i64 @test16.2() {
; CHECK-LABEL: @test16.2(
; CHECK-NEXT: ret i64 -14
;
%v = load i64, ptr getelementptr inbounds ([4 x ptr], ptr @gv7, i64 0, i64 1), align 8
ret i64 %v
}
define i64 @test16.3() {
; CHECK-LABEL: @test16.3(
; CHECK-NEXT: ret i64 0
;
%v = load i64, ptr getelementptr inbounds ([4 x ptr], ptr @gv7, i64 0, i64 2), align 8
ret i64 %v
}
@g7 = constant {[0 x i32], [0 x i8], ptr} { [0 x i32] poison, [0 x i8] poison, ptr null }
define ptr @test_leading_zero_size_elems() {
; CHECK-LABEL: @test_leading_zero_size_elems(
; CHECK-NEXT: ret ptr null
;
%v = load ptr, ptr @g7
ret ptr %v
}
@g8 = constant {[4294967295 x [0 x i32]], i64} { [4294967295 x [0 x i32]] poison, i64 123 }
define i64 @test_leading_zero_size_elems_big() {
; CHECK-LABEL: @test_leading_zero_size_elems_big(
; CHECK-NEXT: ret i64 123
;
%v = load i64, ptr @g8
ret i64 %v
}
@g9 = constant [4294967295 x [0 x i32]] zeroinitializer
define i64 @test_array_of_zero_size_array() {
; CHECK-LABEL: @test_array_of_zero_size_array(
; CHECK-NEXT: ret i64 poison
;
%v = load i64, ptr @g9
ret i64 %v
}
@g_undef = constant { i128 } undef
define ptr @test_undef_aggregate() {
; CHECK-LABEL: @test_undef_aggregate(
; CHECK-NEXT: ret ptr undef
;
%v = load ptr, ptr @g_undef
ret ptr %v
}
@g_poison = constant { i128 } poison
define ptr @test_poison_aggregate() {
; CHECK-LABEL: @test_poison_aggregate(
; CHECK-NEXT: ret ptr poison
;
%v = load ptr, ptr @g_poison
ret ptr %v
}
@g11 = constant <{ [8 x i8], [8 x i8] }> <{ [8 x i8] poison, [8 x i8] zeroinitializer }>, align 4
define ptr @test_trailing_zero_gep_index() {
; CHECK-LABEL: @test_trailing_zero_gep_index(
; CHECK-NEXT: ret ptr null
;
%v = load ptr, ptr getelementptr inbounds (<{ [8 x i8], [8 x i8] }>, ptr @g11, i32 0, i32 1, i32 0), align 4
ret ptr %v
}
define { i64, i64 } @test_load_struct() {
; CHECK-LABEL: @test_load_struct(
; CHECK-NEXT: ret { i64, i64 } { i64 123, i64 112312312 }
;
%v = load { i64, i64 }, ptr @g3
ret { i64, i64 } %v
}
@m64 = internal constant [2 x i64] zeroinitializer
@idx = external global i32
; This should not try to create an x86_mmx null value.
define x86_mmx @load_mmx() {
; CHECK-LABEL: @load_mmx(
; CHECK-NEXT: [[TEMP:%.*]] = load x86_mmx, ptr getelementptr ([2 x i64], ptr @m64, i64 0, i64 ptrtoint (ptr @idx to i64)), align 8
; CHECK-NEXT: ret x86_mmx [[TEMP]]
;
%temp = load x86_mmx, ptr getelementptr ([2 x i64], ptr @m64, i64 0, i64 ptrtoint (ptr @idx to i64))
ret x86_mmx %temp
}
@g_offset = external global i64
@g_neg_one_vec = constant <4 x i8> <i8 -1, i8 -1, i8 -1, i8 -1>
define i8 @load_neg_one_at_unknown_offset() {
; CHECK-LABEL: @load_neg_one_at_unknown_offset(
; CHECK-NEXT: ret i8 -1
;
%v = load i8, ptr getelementptr (<4 x i8>, ptr @g_neg_one_vec, i64 0, i64 ptrtoint (ptr @g_offset to i64))
ret i8 %v
}
@g_with_padding = constant { i32, [4 x i8] } { i32 0, [4 x i8] poison }
define i32 @load_padding() {
; CHECK-LABEL: @load_padding(
; CHECK-NEXT: ret i32 poison
;
%v = load i32, ptr getelementptr (i32, ptr @g_with_padding, i64 1)
ret i32 %v
}
@g_all_poison = constant { i32, [4 x i8] } poison
; Same as the previous case, but with an all-poison initializer.
define i32 @load_all_poison() {
; CHECK-LABEL: @load_all_poison(
; CHECK-NEXT: ret i32 poison
;
%v = load i32, ptr getelementptr (i32, ptr @g_all_poison, i64 1)
ret i32 %v
}
@g_i8_data = constant [16 x i8] c"\01\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00"
define ptr @load_ptr_from_i8_data() {
; LE-LABEL: @load_ptr_from_i8_data(
; LE-NEXT: ret ptr inttoptr (i64 1 to ptr)
;
; BE-LABEL: @load_ptr_from_i8_data(
; BE-NEXT: ret ptr inttoptr (i64 72057594037927936 to ptr)
;
%v = load ptr, ptr @g_i8_data
ret ptr %v
}
define ptr addrspace(2) @load_non_integral_ptr_from_i8_data() {
; CHECK-LABEL: @load_non_integral_ptr_from_i8_data(
; CHECK-NEXT: [[V:%.*]] = load ptr addrspace(2), ptr @g_i8_data, align 8
; CHECK-NEXT: ret ptr addrspace(2) [[V]]
;
%v = load ptr addrspace(2), ptr @g_i8_data
ret ptr addrspace(2) %v
}
@g_i1 = constant i1 true
define i8 @load_i8_from_i1() {
; CHECK-LABEL: @load_i8_from_i1(
; CHECK-NEXT: [[V:%.*]] = load i8, ptr @g_i1, align 1
; CHECK-NEXT: ret i8 [[V]]
;
%v = load i8, ptr @g_i1
ret i8 %v
}
@global9 = internal constant i9 -1
; Reproducer for https://github.com/llvm/llvm-project/issues/81793
define i8 @load_i8_from_i9() {
; CHECK-LABEL: @load_i8_from_i9(
; CHECK-NEXT: [[V:%.*]] = load i8, ptr @global9, align 1
; CHECK-NEXT: ret i8 [[V]]
;
%v = load i8, ptr @global9
ret i8 %v
}
define i9 @load_i9_from_i9() {
; CHECK-LABEL: @load_i9_from_i9(
; CHECK-NEXT: ret i9 -1
;
%v = load i9, ptr @global9
ret i9 %v
}
; Reproducer for https://github.com/llvm/llvm-project/issues/81793
define i16 @load_i16_from_i17_store(ptr %p) {
; CHECK-LABEL: @load_i16_from_i17_store(
; CHECK-NEXT: store i17 -1, ptr [[P:%.*]], align 4
; CHECK-NEXT: [[V:%.*]] = load i16, ptr @global9, align 2
; CHECK-NEXT: ret i16 [[V]]
;
store i17 -1, ptr %p
%v = load i16, ptr @global9
ret i16 %v
}
@global128 = internal constant i128 1125899906842625
define i128 @load-128bit(){
; CHECK-LABEL: @load-128bit(
; CHECK-NEXT: ret i128 1125899906842625
;
%1 = load i128, ptr @global128, align 4
ret i128 %1
}
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