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llvm-mirror/test/Transforms/IRCE/clamp.ll
Roman Lebedev eb30ce19c4 [NFCI] SCEVExpander: emit intrinsics for integral {u,s}{min,max} SCEV expressions
These intrinsics, not the icmp+select are the canonical form nowadays,
so we might as well directly emit them.

This should not cause any regressions, but if it does,
then then they would needed to be fixed regardless.

Note that this doesn't deal with `SCEVExpander::isHighCostExpansion()`,
but that is a pessimization, not a correctness issue.

Additionally, the non-intrinsic form has issues with undef,
see https://reviews.llvm.org/D88287#2587863
2021-03-06 21:52:46 +03:00

95 lines
3.9 KiB
LLVM

; RUN: opt -verify-loop-info -irce-print-changed-loops -irce -S < %s 2>&1 | FileCheck %s
; RUN: opt -verify-loop-info -irce-print-changed-loops -passes='require<branch-prob>,irce' -S < %s 2>&1 | FileCheck %s
; The test demonstrates that incorrect behavior of Clamp may lead to incorrect
; calculation of post-loop exit condition.
; CHECK-LABEL: irce: in function test_01: constrained Loop at depth 1 containing: %loop<header><exiting>,%in_bounds<exiting>,%not_zero<latch><exiting>
; CHECK-NOT: irce: in function test_02: constrained Loop
define void @test_01() {
; CHECK-LABEL: test_01
entry:
%indvars.iv.next467 = add nuw nsw i64 2, 1
%length.i167 = load i32, i32 addrspace(1)* undef, align 8
%tmp21 = zext i32 %length.i167 to i64
%tmp34 = load atomic i32, i32 addrspace(1)* undef unordered, align 4
%tmp35 = add i32 %tmp34, -9581
%tmp36 = icmp ugt i32 %length.i167, 1
br i1 %tmp36, label %preheader, label %exit
exit: ; preds = %in_bounds, %loop, %not_zero, %entry
ret void
preheader: ; preds = %entry
; CHECK: preheader:
; CHECK-NEXT: %length_gep.i146 = getelementptr inbounds i8, i8 addrspace(1)* undef, i64 8
; CHECK-NEXT: %length_gep_typed.i147 = bitcast i8 addrspace(1)* undef to i32 addrspace(1)*
; CHECK-NEXT: %tmp43 = icmp ult i64 %indvars.iv.next467, %tmp21
; CHECK-NEXT: %exit.mainloop.at = call i64 @llvm.umax.i64(i64 %tmp21, i64 1)
; CHECK-NEXT: [[C1:%[^ ]+]] = icmp ult i64 1, %exit.mainloop.at
; CHECK-NEXT: br i1 [[C1]], label %loop.preheader, label %main.pseudo.exit
%length_gep.i146 = getelementptr inbounds i8, i8 addrspace(1)* undef, i64 8
%length_gep_typed.i147 = bitcast i8 addrspace(1)* undef to i32 addrspace(1)*
%tmp43 = icmp ult i64 %indvars.iv.next467, %tmp21
br label %loop
not_zero: ; preds = %in_bounds
; CHECK: not_zero:
; CHECK: %tmp56 = icmp ult i64 %indvars.iv.next, %tmp21
; CHECK-NEXT: [[COND:%[^ ]+]] = icmp ult i64 %indvars.iv.next, %exit.mainloop.at
; CHECK-NEXT: br i1 [[COND]], label %loop, label %main.exit.selector
%tmp51 = trunc i64 %indvars.iv.next to i32
%tmp53 = mul i32 %tmp51, %tmp51
%tmp54 = add i32 %tmp53, -9582
%tmp55 = add i32 %tmp54, %tmp62
%tmp56 = icmp ult i64 %indvars.iv.next, %tmp21
br i1 %tmp56, label %loop, label %exit
loop: ; preds = %not_zero, %preheader
%tmp62 = phi i32 [ 1, %preheader ], [ %tmp55, %not_zero ]
%indvars.iv750 = phi i64 [ 1, %preheader ], [ %indvars.iv.next, %not_zero ]
%length.i148 = load i32, i32 addrspace(1)* %length_gep_typed.i147, align 8
%tmp68 = zext i32 %length.i148 to i64
%tmp97 = icmp ult i64 2, %tmp68
%or.cond = and i1 %tmp43, %tmp97
%tmp99 = icmp ult i64 %indvars.iv750, %tmp21
%or.cond1 = and i1 %or.cond, %tmp99
br i1 %or.cond1, label %in_bounds, label %exit
in_bounds: ; preds = %loop
%indvars.iv.next = add nuw nsw i64 %indvars.iv750, 3
%tmp107 = icmp ult i64 %indvars.iv.next, 2
br i1 %tmp107, label %not_zero, label %exit
}
define void @test_02() {
; Now IRCE is smart enough to understand that the safe range here is empty.
; Previously it executed the entire loop in safe preloop and never actually
; entered the main loop.
entry:
br label %loop
loop: ; preds = %in_bounds, %entry
%iv1 = phi i64 [ 3, %entry ], [ %iv1.next, %in_bounds ]
%iv2 = phi i64 [ 4294967295, %entry ], [ %iv2.next, %in_bounds ]
%iv2.offset = add i64 %iv2, 1
%rc = icmp ult i64 %iv2.offset, 400
br i1 %rc, label %in_bounds, label %bci_321
bci_321: ; preds = %in_bounds, %loop
ret void
in_bounds: ; preds = %loop
%iv1.next = add nuw nsw i64 %iv1, 2
%iv2.next = add nuw nsw i64 %iv2, 2
%cond = icmp ugt i64 %iv1, 204
br i1 %cond, label %bci_321, label %loop
}