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clang-p2996/llvm/test/Transforms/LoopVectorize/iv-select-cmp.ll
Ramkumar Ramachandra 04b1276ad3 LoopVectorize/iv-select-cmp: add tests for truncated IV 
The current tests in iv-select-cmp.ll are not representative of clang
output of common real-world C programs, which are often written with i32
induction vars, as opposed to i64 induction vars. Hence, add five tests
corresponding to the following programs:

  int test(int *a, int n) {
    int rdx = 331;
    for (int i = 0; i < n; i++) {
      if (a[i] > 3)
        rdx = i;
    }
    return rdx;
  }

  int test(int *a) {
    int rdx = 331;
    for (int i = 0; i < 20000; i++) {
      if (a[i] > 3)
        rdx = i;
    }
    return rdx;
  }

  int test(int *a, long n) {
    int rdx = 331;
    for (int i = 0; i < n; i++) {
      if (a[i] > 3)
        rdx = i;
    }
    return rdx;
  }

  int test(int *a, unsigned n) {
    int rdx = 331;
    for (int i = 0; i < n; i++) {
      if (a[i] > 3)
        rdx = i;
    }
    return rdx;
  }

  int test(int *a) {
    int rdx = 331;
    for (long i = INT_MIN - 1; i < UINT_MAX; i++) {
      if (a[i] > 3)
        rdx = i;
    }
    return rdx;
  }

The first two can theoretically be vectorized without a runtime-check,
while the third and fourth cannot. The fifth cannot be vectorized, even
with a runtime-check.

This issue was found while reviewing D150851.

Differential Revision: https://reviews.llvm.org/D156124
2023-08-30 13:09:37 +01:00

478 lines
18 KiB
LLVM
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; RUN: opt -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S < %s | FileCheck %s --check-prefix=CHECK
; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=4 -S < %s | FileCheck %s --check-prefix=CHECK
; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=1 -S < %s | FileCheck %s --check-prefix=CHECK
define i64 @select_icmp_const_1(ptr nocapture readonly %a, i64 %n) {
; CHECK-LABEL: define i64 @select_icmp_const_1
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
%rdx = phi i64 [ %cond, %for.body ], [ 3, %entry ]
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv
%0 = load i64, ptr %arrayidx, align 8
%cmp2 = icmp eq i64 %0, 3
%cond = select i1 %cmp2, i64 %iv, i64 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i64 %cond
}
define i64 @select_icmp_const_2(ptr nocapture readonly %a, i64 %n) {
; CHECK-LABEL: define i64 @select_icmp_const_2
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
%rdx = phi i64 [ %cond, %for.body ], [ 3, %entry ]
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv
%0 = load i64, ptr %arrayidx, align 8
%cmp2 = icmp eq i64 %0, 3
%cond = select i1 %cmp2, i64 %rdx, i64 %iv
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i64 %cond
}
define i64 @select_icmp_const_3_variable_rdx_start(ptr nocapture readonly %a, i64 %rdx.start, i64 %n) {
; CHECK-LABEL: define i64 @select_icmp_const_3_variable_rdx_start
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
%rdx = phi i64 [ %cond, %for.body ], [ %rdx.start, %entry ]
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv
%0 = load i64, ptr %arrayidx, align 8
%cmp2 = icmp eq i64 %0, 3
%cond = select i1 %cmp2, i64 %iv, i64 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i64 %cond
}
define i64 @select_fcmp_const_fast(ptr nocapture readonly %a, i64 %n) {
; CHECK-LABEL: define i64 @select_fcmp_const_fast
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
%rdx = phi i64 [ %cond, %for.body ], [ 2, %entry ]
%arrayidx = getelementptr inbounds float, ptr %a, i64 %iv
%0 = load float, ptr %arrayidx, align 4
%cmp2 = fcmp fast ueq float %0, 3.0
%cond = select i1 %cmp2, i64 %iv, i64 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i64 %cond
}
define i64 @select_fcmp_const(ptr nocapture readonly %a, i64 %n) {
; CHECK-LABEL: define i64 @select_fcmp_const
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
%rdx = phi i64 [ %cond, %for.body ], [ 2, %entry ]
%arrayidx = getelementptr inbounds float, ptr %a, i64 %iv
%0 = load float, ptr %arrayidx, align 4
%cmp2 = fcmp ueq float %0, 3.0
%cond = select i1 %cmp2, i64 %iv, i64 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i64 %cond
}
define i64 @select_icmp(ptr nocapture readonly %a, ptr nocapture readonly %b, i64 %rdx.start, i64 %n) {
; CHECK-LABEL: define i64 @select_icmp
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
%rdx = phi i64 [ %cond, %for.body ], [ %rdx.start, %entry ]
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv
%0 = load i64, ptr %arrayidx, align 8
%arrayidx1 = getelementptr inbounds i64, ptr %b, i64 %iv
%1 = load i64, ptr %arrayidx1, align 8
%cmp2 = icmp sgt i64 %0, %1
%cond = select i1 %cmp2, i64 %iv, i64 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i64 %cond
}
define i64 @select_fcmp(ptr nocapture readonly %a, ptr nocapture readonly %b, i64 %rdx.start, i64 %n) {
; CHECK-LABEL: define i64 @select_fcmp
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
%rdx = phi i64 [ %cond, %for.body ], [ %rdx.start, %entry ]
%arrayidx = getelementptr inbounds float, ptr %a, i64 %iv
%0 = load float, ptr %arrayidx, align 4
%arrayidx1 = getelementptr inbounds float, ptr %b, i64 %iv
%1 = load float, ptr %arrayidx1, align 4
%cmp2 = fcmp ogt float %0, %1
%cond = select i1 %cmp2, i64 %iv, i64 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i64 %cond
}
define i64 @select_icmp_min_valid_iv_start(ptr nocapture readonly %a, ptr nocapture readonly %b, i64 %rdx.start, i64 %n) {
; CHECK-LABEL: define i64 @select_icmp_min_valid_iv_start
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv.j = phi i64 [ %inc3, %for.body ], [ -9223372036854775807, %entry]
%iv.i = phi i64 [ %inc, %for.body ], [ 0, %entry ]
%rdx = phi i64 [ %cond, %for.body ], [ %rdx.start, %entry ]
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv.i
%0 = load i64, ptr %arrayidx, align 8
%arrayidx1 = getelementptr inbounds i64, ptr %b, i64 %iv.i
%1 = load i64, ptr %arrayidx1, align 8
%cmp2 = icmp sgt i64 %0, %1
%cond = select i1 %cmp2, i64 %iv.j, i64 %rdx
%inc = add nuw nsw i64 %iv.i, 1
%inc3 = add nsw i64 %iv.j, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i64 %cond
}
; Negative tests
; This test can theoretically be vectorized without a runtime-check, by
; pattern-matching on the constructs that are introduced by IndVarSimplify.
; We can check two things:
; %1 = trunc i64 %iv to i32
; This indicates that the %iv is truncated to i32. We can then check the loop
; guard is a signed i32:
; %cmp.sgt = icmp sgt i32 %n, 0
; and successfully vectorize the case without a runtime-check.
define i32 @not_vectorized_select_icmp_const_truncated_iv_widened_exit(ptr nocapture readonly %a, i32 %n) {
; CHECK-LABEL: define i32 @not_vectorized_select_icmp_const_truncated_iv_widened_exit
; CHECK-NOT: vector.body:
;
entry:
%cmp.sgt = icmp sgt i32 %n, 0
br i1 %cmp.sgt, label %for.body.preheader, label %exit
for.body.preheader: ; preds = %entry
%wide.trip.count = zext i32 %n to i64
br label %for.body
for.body: ; preds = %for.body.preheader, %for.body
%iv = phi i64 [ 0, %for.body.preheader ], [ %inc, %for.body ]
%rdx = phi i32 [ 331, %for.body.preheader ], [ %spec.select, %for.body ]
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv
%0 = load i64, ptr %arrayidx, align 8
%cmp = icmp sgt i64 %0, 3
%1 = trunc i64 %iv to i32
%spec.select = select i1 %cmp, i32 %1, i32 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %wide.trip.count
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body, %entry
%rdx.lcssa = phi i32 [ 331, %entry ], [ %spec.select, %for.body ]
ret i32 %rdx.lcssa
}
; This test can theoretically be vectorized without a runtime-check, by
; pattern-matching on the constructs that are introduced by IndVarSimplify.
; We can check two things:
; %1 = trunc i64 %iv to i32
; This indicates that the %iv is truncated to i32. We can then check the loop
; exit condition, which compares to a constant that fits within i32:
; %exitcond.not = icmp eq i64 %inc, 20000
; and successfully vectorize the case without a runtime-check.
define i32 @not_vectorized_select_icmp_const_truncated_iv_const_exit(ptr nocapture readonly %a) {
; CHECK-LABEL: define i32 @not_vectorized_select_icmp_const_truncated_iv_const_exit
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ 0, %entry ], [ %inc, %for.body ]
%rdx = phi i32 [ 331, %entry ], [ %spec.select, %for.body ]
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv
%0 = load i64, ptr %arrayidx, align 8
%cmp = icmp sgt i64 %0, 3
%1 = trunc i64 %iv to i32
%spec.select = select i1 %cmp, i32 %1, i32 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, 20000
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i32 %spec.select
}
; This test can theoretically be vectorized, but only with a runtime-check.
; The construct that are introduced by IndVarSimplify is:
; %1 = trunc i64 %iv to i32
; However, the loop guard is an i64:
; %cmp.sgt = icmp sgt i64 %n, 0
; We cannot guarantee that %iv won't overflow an i32 value (and hence hit the
; sentinel value), and need a runtime-check to vectorize this case.
define i32 @not_vectorized_select_icmp_const_truncated_iv_unwidened_exit(ptr nocapture readonly %a, i64 %n) {
; CHECK-LABEL: define i32 @not_vectorized_select_icmp_const_truncated_iv_unwidened_exit
; CHECK-NOT: vector.body:
;
entry:
%cmp.sgt = icmp sgt i64 %n, 0
br i1 %cmp.sgt, label %for.body, label %exit
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ 0, %entry ], [ %inc, %for.body ]
%rdx = phi i32 [ 331, %entry ], [ %spec.select, %for.body ]
%arrayidx = getelementptr inbounds i32, ptr %a, i64 %iv
%0 = load i32, ptr %arrayidx, align 4
%cmp = icmp sgt i32 %0, 3
%1 = trunc i64 %iv to i32
%spec.select = select i1 %cmp, i32 %1, i32 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body, %entry
%rdx.lcssa = phi i32 [ 331, %entry ], [ %spec.select, %for.body ]
ret i32 %rdx.lcssa
}
; This test can theoretically be vectorized, but only with a runtime-check.
; The construct that are introduced by IndVarSimplify is:
; %1 = trunc i64 %iv to i32
; However, the loop guard is unsigned:
; %cmp.not = icmp eq i32 %n, 0
; We cannot guarantee that %iv won't overflow an i32 value (and hence hit the
; sentinel value), and need a runtime-check to vectorize this case.
define i32 @not_vectorized_select_icmp_const_truncated_iv_unsigned_loop_guard(ptr nocapture readonly %a, i32 %n) {
; CHECK-LABEL: define i32 @not_vectorized_select_icmp_const_truncated_iv_unsigned_loop_guard
; CHECK-NOT: vector.body:
;
entry:
%cmp.not = icmp eq i32 %n, 0
br i1 %cmp.not, label %exit, label %for.body.preheader
for.body.preheader: ; preds = %entry
%wide.trip.count = zext i32 %n to i64
br label %for.body
for.body: ; preds = %for.body.preheader, %for.body
%iv = phi i64 [ 0, %for.body.preheader ], [ %inc, %for.body ]
%rdx = phi i32 [ 331, %for.body.preheader ], [ %spec.select, %for.body ]
%arrayidx = getelementptr inbounds i32, ptr %a, i64 %iv
%0 = load i32, ptr %arrayidx, align 4
%cmp1 = icmp sgt i32 %0, 3
%1 = trunc i64 %iv to i32
%spec.select = select i1 %cmp1, i32 %1, i32 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %wide.trip.count
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body, %entry
%rdx.lcssa = phi i32 [ 331, %entry ], [ %spec.select, %for.body ]
ret i32 %rdx.lcssa
}
; This test cannot be vectorized, even with a runtime check.
; The construct that are introduced by IndVarSimplify is:
; %1 = trunc i64 %iv to i32
; However, the loop exit condition is a constant that overflows i32:
; %exitcond.not = icmp eq i64 %inc, 4294967294
; Hence, the i32 will most certainly wrap and hit the sentinel value, and we
; cannot vectorize this case.
define i32 @not_vectorized_select_icmp_truncated_iv_out_of_bound(ptr nocapture readonly %a) {
; CHECK-LABEL: define i32 @not_vectorized_select_icmp_truncated_iv_out_of_bound
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ 2147483646, %entry ], [ %inc, %for.body ]
%rdx = phi i32 [ 331, %entry ], [ %spec.select, %for.body ]
%arrayidx = getelementptr inbounds i32, ptr %a, i64 %iv
%0 = load i32, ptr %arrayidx, align 4
%cmp = icmp sgt i32 %0, 3
%conv = trunc i64 %iv to i32
%spec.select = select i1 %cmp, i32 %conv, i32 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, 4294967294
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i32 %spec.select
}
define float @not_vectorized_select_float_induction_icmp(ptr nocapture readonly %a, ptr nocapture readonly %b, float %rdx.start, i64 %n) {
; CHECK-LABEL: @not_vectorized_select_float_induction_icmp
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
%fiv = phi float [ %conv3, %for.body ], [ 0.000000e+00, %entry ]
%rdx = phi float [ %cond, %for.body ], [ %rdx.start, %entry ]
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv
%0 = load i64, ptr %arrayidx, align 8
%arrayidx1 = getelementptr inbounds i64, ptr %b, i64 %iv
%1 = load i64, ptr %arrayidx1, align 8
%cmp2 = icmp sgt i64 %0, %1
%cond = select i1 %cmp2, float %fiv, float %rdx
%conv3 = fadd float %fiv, 1.000000e+00
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret float %cond
}
define i64 @not_vectorized_select_decreasing_induction_icmp_const_start(ptr nocapture readonly %a) {
; CHECK-LABEL: @not_vectorized_select_decreasing_induction_icmp_const_start
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ 19999, %entry ], [ %dec, %for.body ]
%rdx = phi i64 [ 331, %entry ], [ %spec.select, %for.body ]
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv
%0 = load i64, ptr %arrayidx, align 8
%cmp = icmp sgt i64 %0, 3
%spec.select = select i1 %cmp, i64 %iv, i64 %rdx
%dec = add nsw i64 %iv, -1
%cmp.not = icmp eq i64 %iv, 0
br i1 %cmp.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i64 %spec.select
}
define i64 @not_vectorized_select_decreasing_induction_icmp_non_const_start(ptr nocapture readonly %a, ptr nocapture readonly %b, i64 %rdx.start, i64 %n) {
; CHECK-LABEL: @not_vectorized_select_decreasing_induction_icmp_non_const_start
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%i.0.in10 = phi i64 [ %iv, %for.body ], [ %n, %entry ]
%rdx = phi i64 [ %cond, %for.body ], [ %rdx.start, %entry ]
%iv = add nsw i64 %i.0.in10, -1
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv
%0 = load i64, ptr %arrayidx, align 8
%arrayidx1 = getelementptr inbounds i64, ptr %b, i64 %iv
%1 = load i64, ptr %arrayidx1, align 8
%cmp2 = icmp sgt i64 %0, %1
%cond = select i1 %cmp2, i64 %iv, i64 %rdx
%cmp = icmp ugt i64 %i.0.in10, 1
br i1 %cmp, label %for.body, label %exit
exit: ; preds = %for.body
ret i64 %cond
}
define i64 @not_vectorized_select_icmp_iv_out_of_bound(ptr nocapture readonly %a, ptr nocapture readonly %b, i64 %rdx.start, i64 %n) {
; CHECK-LABEL: @not_vectorized_select_icmp_iv_out_of_bound
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv.j = phi i64 [ %inc3, %for.body ], [ -9223372036854775808, %entry]
%iv.i = phi i64 [ %inc, %for.body ], [ 0, %entry ]
%rdx = phi i64 [ %cond, %for.body ], [ %rdx.start, %entry ]
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv.i
%0 = load i64, ptr %arrayidx, align 8
%arrayidx1 = getelementptr inbounds i64, ptr %b, i64 %iv.i
%1 = load i64, ptr %arrayidx1, align 8
%cmp2 = icmp sgt i64 %0, %1
%cond = select i1 %cmp2, i64 %iv.j, i64 %rdx
%inc = add nuw nsw i64 %iv.i, 1
%inc3 = add nsw i64 %iv.j, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i64 %cond
}
define i64 @not_vectorized_select_icmp_non_const_iv_start_value(ptr nocapture readonly %a, ptr nocapture readonly %b, i64 %ivstart, i64 %rdx.start, i64 %n) {
; CHECK-LABEL: define i64 @not_vectorized_select_icmp_non_const_iv_start_value
; CHECK-NOT: vector.body:
;
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%iv = phi i64 [ %inc, %for.body ], [ %ivstart, %entry ]
%rdx = phi i64 [ %cond, %for.body ], [ %rdx.start, %entry ]
%arrayidx = getelementptr inbounds i64, ptr %a, i64 %iv
%0 = load i64, ptr %arrayidx, align 8
%arrayidx1 = getelementptr inbounds i64, ptr %b, i64 %iv
%1 = load i64, ptr %arrayidx1, align 8
%cmp2 = icmp sgt i64 %0, %1
%cond = select i1 %cmp2, i64 %iv, i64 %rdx
%inc = add nuw nsw i64 %iv, 1
%exitcond.not = icmp eq i64 %inc, %n
br i1 %exitcond.not, label %exit, label %for.body
exit: ; preds = %for.body
ret i64 %cond
}
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