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[LLVM][ConstFolds] Verify a scalar src before attempting scalar->vector bitcast transformation. #111149

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Merged
merged 1 commit into from
Oct 8, 2024
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[LLVM][ConstFolds] Verify a scalar src before attempting scalar->vector bitcast transformation. #111149

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3 changes: 2 additions & 1 deletion llvm/lib/Analysis/ConstantFolding.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -145,7 +145,8 @@ Constant *FoldBitCast(Constant *C, Type *DestTy, const DataLayout &DL) {

// If this is a scalar -> vector cast, convert the input into a <1 x scalar>
// vector so the code below can handle it uniformly.
if (isa<ConstantFP>(C) || isa<ConstantInt>(C)) {
if (!isa<VectorType>(C->getType()) &&
(isa<ConstantFP>(C) || isa<ConstantInt>(C))) {
Constant *Ops = C; // don't take the address of C!
return FoldBitCast(ConstantVector::get(Ops), DestTy, DL);
}
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5 changes: 3 additions & 2 deletions llvm/lib/IR/ConstantFold.cpp
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Expand Up @@ -81,8 +81,9 @@ static Constant *FoldBitCast(Constant *V, Type *DestTy) {
// Canonicalize scalar-to-vector bitcasts into vector-to-vector bitcasts
// This allows for other simplifications (although some of them
// can only be handled by Analysis/ConstantFolding.cpp).
if (isa<ConstantInt>(V) || isa<ConstantFP>(V))
return ConstantExpr::getBitCast(ConstantVector::get(V), DestPTy);
if (!isa<VectorType>(SrcTy))
if (isa<ConstantInt>(V) || isa<ConstantFP>(V))
return ConstantExpr::getBitCast(ConstantVector::get(V), DestPTy);
return nullptr;
}

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59 changes: 45 additions & 14 deletions llvm/test/Transforms/InstSimplify/bitcast-vector-fold.ll
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@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=instsimplify -S | FileCheck %s
; RUN: opt < %s -passes=instsimplify -S | FileCheck %s --check-prefixes=CHECK,CONSTVEC
; RUN: opt < %s -passes=instsimplify -use-constant-fp-for-fixed-length-splat -use-constant-int-for-fixed-length-splat -S | FileCheck %s --check-prefixes=CHECK,CONSTSPLAT
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-f64:32:64-v64:64:64-v128:128:128"

define <2 x i64> @test1() {
Expand Down Expand Up @@ -67,43 +68,59 @@ define <4 x i32> @test8(<1 x i64> %y) {
}

define <4 x i32> @test9(<1 x i64> %y) {
; CHECK-LABEL: @test9(
; CHECK-NEXT: ret <4 x i32> <i32 -1, i32 -1, i32 -1, i32 -1>
; CONSTVEC-LABEL: @test9(
; CONSTVEC-NEXT: ret <4 x i32> <i32 -1, i32 -1, i32 -1, i32 -1>
;
; CONSTSPLAT-LABEL: @test9(
; CONSTSPLAT-NEXT: ret <4 x i32> splat (i32 -1)
;
%c = bitcast <2 x i64> <i64 -1, i64 -1> to <4 x i32>
ret <4 x i32> %c
}

define <1 x i1> @test10() {
; CHECK-LABEL: @test10(
; CHECK-NEXT: [[RET:%.*]] = icmp eq <1 x i64> <i64 bitcast (<1 x double> <double 0xFFFFFFFFFFFFFFFF> to i64)>, zeroinitializer
; CHECK-NEXT: ret <1 x i1> [[RET]]
; CONSTVEC-LABEL: @test10(
; CONSTVEC-NEXT: [[RET:%.*]] = icmp eq <1 x i64> <i64 bitcast (<1 x double> <double 0xFFFFFFFFFFFFFFFF> to i64)>, zeroinitializer
; CONSTVEC-NEXT: ret <1 x i1> [[RET]]
;
; CONSTSPLAT-LABEL: @test10(
; CONSTSPLAT-NEXT: [[RET:%.*]] = icmp eq <1 x i64> splat (i64 -1), zeroinitializer
; CONSTSPLAT-NEXT: ret <1 x i1> [[RET]]
;
%ret = icmp eq <1 x i64> <i64 bitcast (<1 x double> <double 0xFFFFFFFFFFFFFFFF> to i64)>, zeroinitializer
ret <1 x i1> %ret
}

; from MultiSource/Benchmarks/Bullet
define <2 x float> @foo() {
; CHECK-LABEL: @foo(
; CHECK-NEXT: ret <2 x float> <float 0xFFFFFFFFE0000000, float 0xFFFFFFFFE0000000>
; CONSTVEC-LABEL: @foo(
; CONSTVEC-NEXT: ret <2 x float> <float 0xFFFFFFFFE0000000, float 0xFFFFFFFFE0000000>
;
; CONSTSPLAT-LABEL: @foo(
; CONSTSPLAT-NEXT: ret <2 x float> splat (float 0xFFFFFFFFE0000000)
;
%cast = bitcast i64 -1 to <2 x float>
ret <2 x float> %cast
}


define <2 x double> @foo2() {
; CHECK-LABEL: @foo2(
; CHECK-NEXT: ret <2 x double> <double 0xFFFFFFFFFFFFFFFF, double 0xFFFFFFFFFFFFFFFF>
; CONSTVEC-LABEL: @foo2(
; CONSTVEC-NEXT: ret <2 x double> <double 0xFFFFFFFFFFFFFFFF, double 0xFFFFFFFFFFFFFFFF>
;
; CONSTSPLAT-LABEL: @foo2(
; CONSTSPLAT-NEXT: ret <2 x double> splat (double 0xFFFFFFFFFFFFFFFF)
;
%cast = bitcast i128 -1 to <2 x double>
ret <2 x double> %cast
}

define <1 x float> @foo3() {
; CHECK-LABEL: @foo3(
; CHECK-NEXT: ret <1 x float> <float 0xFFFFFFFFE0000000>
; CONSTVEC-LABEL: @foo3(
; CONSTVEC-NEXT: ret <1 x float> <float 0xFFFFFFFFE0000000>
;
; CONSTSPLAT-LABEL: @foo3(
; CONSTSPLAT-NEXT: ret <1 x float> splat (float 0xFFFFFFFFE0000000)
;
%cast = bitcast i32 -1 to <1 x float>
ret <1 x float> %cast
Expand All @@ -126,8 +143,11 @@ define double @foo5() {
}

define <2 x double> @foo6() {
; CHECK-LABEL: @foo6(
; CHECK-NEXT: ret <2 x double> <double 0xFFFFFFFFFFFFFFFF, double 0xFFFFFFFFFFFFFFFF>
; CONSTVEC-LABEL: @foo6(
; CONSTVEC-NEXT: ret <2 x double> <double 0xFFFFFFFFFFFFFFFF, double 0xFFFFFFFFFFFFFFFF>
;
; CONSTSPLAT-LABEL: @foo6(
; CONSTSPLAT-NEXT: ret <2 x double> splat (double 0xFFFFFFFFFFFFFFFF)
;
%cast = bitcast <4 x i32><i32 -1, i32 -1, i32 -1, i32 -1> to <2 x double>
ret <2 x double> %cast
Expand Down Expand Up @@ -276,3 +296,14 @@ define <16 x i8> @bitcast_constexpr_16i8_8i16_u256uuu256uu() {
%cast = bitcast <8 x i16><i16 undef, i16 256, i16 undef, i16 undef, i16 undef, i16 256, i16 undef, i16 undef> to <16 x i8>
ret <16 x i8> %cast
}

define <1 x i32> @bitcast_constexpr_scalar_fp_to_vector_int() {
; CONSTVEC-LABEL: @bitcast_constexpr_scalar_fp_to_vector_int(
; CONSTVEC-NEXT: ret <1 x i32> <i32 1065353216>
;
; CONSTSPLAT-LABEL: @bitcast_constexpr_scalar_fp_to_vector_int(
; CONSTSPLAT-NEXT: ret <1 x i32> bitcast (<1 x float> splat (float 1.000000e+00) to <1 x i32>)
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This one should still fold...

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Yes, but I'm focusing on fixing the bugs related to vector Constant{Int,FP} before aligning the optimisation side of things.

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I'm just concerned that we'll forget about it if it's not right in front of our eyes :)

;
%res = bitcast float 1.0 to <1 x i32>
ret <1 x i32> %res
}
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