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llvm-mirror/test/Transforms/LoopVectorize/float-minmax-instruction-flag.ll
Sanjay Patel 3dbd723c6c [IR] allow fast-math-flags on select of FP values 
This is a minimal start to correcting a problem most directly discussed in PR38086:
https://bugs.llvm.org/show_bug.cgi?id=38086

We have been hacking around a limitation for FP select patterns by using the
fast-math-flags on the condition of the select rather than the select itself.
This patch just allows FMF to appear with the 'select' opcode. No changes are
needed to "FPMathOperator" because it already includes select-of-FP because
that definition is based on the (return) value type.

Once we have this ability, we can start correcting and adding IR transforms
to use the FMF on a 'select' instruction. The instcombine and vectorizer test
diffs only show that the IRBuilder change is behaving as expected by applying
an FMF guard value to 'select'.

For reference:
rL241901 - allowed FMF with fcmp
rL255555 - allowed FMF with FP calls

Differential Revision: https://reviews.llvm.org/D61917

llvm-svn: 361401
2019-05-22 15:50:46 +00:00

162 lines
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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -loop-vectorize -force-vector-width=4 -S | FileCheck %s
; The function finds the smallest value from a float vector.
; Check if vectorization is enabled by instruction flag `fcmp nnan`.
define float @minloop(float* nocapture readonly %arg) {
; CHECK-LABEL: @minloop(
; CHECK-NEXT: top:
; CHECK-NEXT: [[T:%.*]] = load float, float* [[ARG:%.*]]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[T1:%.*]] = phi i64 [ [[T7:%.*]], [[LOOP]] ], [ 1, [[TOP:%.*]] ]
; CHECK-NEXT: [[T2:%.*]] = phi float [ [[T6:%.*]], [[LOOP]] ], [ [[T]], [[TOP]] ]
; CHECK-NEXT: [[T3:%.*]] = getelementptr float, float* [[ARG]], i64 [[T1]]
; CHECK-NEXT: [[T4:%.*]] = load float, float* [[T3]], align 4
; CHECK-NEXT: [[T5:%.*]] = fcmp nnan olt float [[T2]], [[T4]]
; CHECK-NEXT: [[T6]] = select i1 [[T5]], float [[T2]], float [[T4]]
; CHECK-NEXT: [[T7]] = add i64 [[T1]], 1
; CHECK-NEXT: [[T8:%.*]] = icmp eq i64 [[T7]], 65537
; CHECK-NEXT: br i1 [[T8]], label [[OUT:%.*]], label [[LOOP]]
; CHECK: out:
; CHECK-NEXT: [[T6_LCSSA:%.*]] = phi float [ [[T6]], [[LOOP]] ]
; CHECK-NEXT: ret float [[T6_LCSSA]]
;
top:
%t = load float, float* %arg
br label %loop
loop: ; preds = %loop, %top
%t1 = phi i64 [ %t7, %loop ], [ 1, %top ]
%t2 = phi float [ %t6, %loop ], [ %t, %top ]
%t3 = getelementptr float, float* %arg, i64 %t1
%t4 = load float, float* %t3, align 4
%t5 = fcmp nnan olt float %t2, %t4
%t6 = select i1 %t5, float %t2, float %t4
%t7 = add i64 %t1, 1
%t8 = icmp eq i64 %t7, 65537
br i1 %t8, label %out, label %loop
out: ; preds = %loop
ret float %t6
}
; Check if vectorization is still enabled by function attribute.
define float @minloopattr(float* nocapture readonly %arg) #0 {
; CHECK-LABEL: @minloopattr(
; CHECK-NEXT: top:
; CHECK-NEXT: [[T:%.*]] = load float, float* [[ARG:%.*]]
; CHECK-NEXT: br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
; CHECK: vector.ph:
; CHECK-NEXT: [[MINMAX_IDENT_SPLATINSERT:%.*]] = insertelement <4 x float> undef, float [[T]], i32 0
; CHECK-NEXT: [[MINMAX_IDENT_SPLAT:%.*]] = shufflevector <4 x float> [[MINMAX_IDENT_SPLATINSERT]], <4 x float> undef, <4 x i32> zeroinitializer
; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
; CHECK: vector.body:
; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[VEC_PHI:%.*]] = phi <4 x float> [ [[MINMAX_IDENT_SPLAT]], [[VECTOR_PH]] ], [ [[TMP6:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[OFFSET_IDX:%.*]] = add i64 1, [[INDEX]]
; CHECK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> undef, i64 [[OFFSET_IDX]], i32 0
; CHECK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> undef, <4 x i32> zeroinitializer
; CHECK-NEXT: [[INDUCTION:%.*]] = add <4 x i64> [[BROADCAST_SPLAT]], <i64 0, i64 1, i64 2, i64 3>
; CHECK-NEXT: [[TMP0:%.*]] = add i64 [[OFFSET_IDX]], 0
; CHECK-NEXT: [[TMP1:%.*]] = getelementptr float, float* [[ARG]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP2:%.*]] = getelementptr float, float* [[TMP1]], i32 0
; CHECK-NEXT: [[TMP3:%.*]] = bitcast float* [[TMP2]] to <4 x float>*
; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <4 x float>, <4 x float>* [[TMP3]], align 4
; CHECK-NEXT: [[TMP4:%.*]] = fcmp olt <4 x float> [[VEC_PHI]], [[WIDE_LOAD]]
; CHECK-NEXT: [[TMP5:%.*]] = extractelement <4 x i1> [[TMP4]], i32 0
; CHECK-NEXT: [[TMP6]] = select <4 x i1> [[TMP4]], <4 x float> [[VEC_PHI]], <4 x float> [[WIDE_LOAD]]
; CHECK-NEXT: [[INDEX_NEXT]] = add i64 [[INDEX]], 4
; CHECK-NEXT: [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], 65536
; CHECK-NEXT: br i1 [[TMP7]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop !0
; CHECK: middle.block:
; CHECK-NEXT: [[RDX_SHUF:%.*]] = shufflevector <4 x float> [[TMP6]], <4 x float> undef, <4 x i32> <i32 2, i32 3, i32 undef, i32 undef>
; CHECK-NEXT: [[RDX_MINMAX_CMP:%.*]] = fcmp fast olt <4 x float> [[TMP6]], [[RDX_SHUF]]
; CHECK-NEXT: [[RDX_MINMAX_SELECT:%.*]] = select fast <4 x i1> [[RDX_MINMAX_CMP]], <4 x float> [[TMP6]], <4 x float> [[RDX_SHUF]]
; CHECK-NEXT: [[RDX_SHUF1:%.*]] = shufflevector <4 x float> [[RDX_MINMAX_SELECT]], <4 x float> undef, <4 x i32> <i32 1, i32 undef, i32 undef, i32 undef>
; CHECK-NEXT: [[RDX_MINMAX_CMP2:%.*]] = fcmp fast olt <4 x float> [[RDX_MINMAX_SELECT]], [[RDX_SHUF1]]
; CHECK-NEXT: [[RDX_MINMAX_SELECT3:%.*]] = select fast <4 x i1> [[RDX_MINMAX_CMP2]], <4 x float> [[RDX_MINMAX_SELECT]], <4 x float> [[RDX_SHUF1]]
; CHECK-NEXT: [[TMP8:%.*]] = extractelement <4 x float> [[RDX_MINMAX_SELECT3]], i32 0
; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 65536, 65536
; CHECK-NEXT: br i1 [[CMP_N]], label [[OUT:%.*]], label [[SCALAR_PH]]
; CHECK: scalar.ph:
; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ 65537, [[MIDDLE_BLOCK]] ], [ 1, [[TOP:%.*]] ]
; CHECK-NEXT: [[BC_MERGE_RDX:%.*]] = phi float [ [[T]], [[TOP]] ], [ [[TMP8]], [[MIDDLE_BLOCK]] ]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[T1:%.*]] = phi i64 [ [[T7:%.*]], [[LOOP]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
; CHECK-NEXT: [[T2:%.*]] = phi float [ [[T6:%.*]], [[LOOP]] ], [ [[BC_MERGE_RDX]], [[SCALAR_PH]] ]
; CHECK-NEXT: [[T3:%.*]] = getelementptr float, float* [[ARG]], i64 [[T1]]
; CHECK-NEXT: [[T4:%.*]] = load float, float* [[T3]], align 4
; CHECK-NEXT: [[T5:%.*]] = fcmp olt float [[T2]], [[T4]]
; CHECK-NEXT: [[T6]] = select i1 [[T5]], float [[T2]], float [[T4]]
; CHECK-NEXT: [[T7]] = add i64 [[T1]], 1
; CHECK-NEXT: [[T8:%.*]] = icmp eq i64 [[T7]], 65537
; CHECK-NEXT: br i1 [[T8]], label [[OUT]], label [[LOOP]], !llvm.loop !2
; CHECK: out:
; CHECK-NEXT: [[T6_LCSSA:%.*]] = phi float [ [[T6]], [[LOOP]] ], [ [[TMP8]], [[MIDDLE_BLOCK]] ]
; CHECK-NEXT: ret float [[T6_LCSSA]]
;
top:
%t = load float, float* %arg
br label %loop
loop: ; preds = %loop, %top
%t1 = phi i64 [ %t7, %loop ], [ 1, %top ]
%t2 = phi float [ %t6, %loop ], [ %t, %top ]
%t3 = getelementptr float, float* %arg, i64 %t1
%t4 = load float, float* %t3, align 4
%t5 = fcmp olt float %t2, %t4
%t6 = select i1 %t5, float %t2, float %t4
%t7 = add i64 %t1, 1
%t8 = icmp eq i64 %t7, 65537
br i1 %t8, label %out, label %loop
out: ; preds = %loop
ret float %t6
}
; Check if vectorization is prevented without the flag or attribute.
define float @minloopnovec(float* nocapture readonly %arg) {
; CHECK-LABEL: @minloopnovec(
; CHECK-NEXT: top:
; CHECK-NEXT: [[T:%.*]] = load float, float* [[ARG:%.*]]
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[T1:%.*]] = phi i64 [ [[T7:%.*]], [[LOOP]] ], [ 1, [[TOP:%.*]] ]
; CHECK-NEXT: [[T2:%.*]] = phi float [ [[T6:%.*]], [[LOOP]] ], [ [[T]], [[TOP]] ]
; CHECK-NEXT: [[T3:%.*]] = getelementptr float, float* [[ARG]], i64 [[T1]]
; CHECK-NEXT: [[T4:%.*]] = load float, float* [[T3]], align 4
; CHECK-NEXT: [[T5:%.*]] = fcmp olt float [[T2]], [[T4]]
; CHECK-NEXT: [[T6]] = select i1 [[T5]], float [[T2]], float [[T4]]
; CHECK-NEXT: [[T7]] = add i64 [[T1]], 1
; CHECK-NEXT: [[T8:%.*]] = icmp eq i64 [[T7]], 65537
; CHECK-NEXT: br i1 [[T8]], label [[OUT:%.*]], label [[LOOP]]
; CHECK: out:
; CHECK-NEXT: [[T6_LCSSA:%.*]] = phi float [ [[T6]], [[LOOP]] ]
; CHECK-NEXT: ret float [[T6_LCSSA]]
;
top:
%t = load float, float* %arg
br label %loop
loop: ; preds = %loop, %top
%t1 = phi i64 [ %t7, %loop ], [ 1, %top ]
%t2 = phi float [ %t6, %loop ], [ %t, %top ]
%t3 = getelementptr float, float* %arg, i64 %t1
%t4 = load float, float* %t3, align 4
%t5 = fcmp olt float %t2, %t4
%t6 = select i1 %t5, float %t2, float %t4
%t7 = add i64 %t1, 1
%t8 = icmp eq i64 %t7, 65537
br i1 %t8, label %out, label %loop
out: ; preds = %loop
ret float %t6
}
attributes #0 = { "no-nans-fp-math"="true" }
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