Florian Hahn 1de3dc7d23 [LV] Bail out early if BTC+1 wraps.
Currently we fail to detect the case where BTC + 1 wraps, i.e. the
vector trip count is 0, In those cases, the minimum iteration count
check will fail, and the vector code will never be executed.

Explicitly check for this condition in computeMaxVF and avoid trying to
vectorize alltogether.

Note that a number of tests needed to be updated, because the vector
loop would never be executed given the input IR.

Fixes https://github.com/llvm/llvm-project/issues/122558.
2025-01-14 22:07:38 +00:00

29 lines
812 B
LLVM

; RUN: opt -mtriple=hexagon -hexagon-autohvx -passes=loop-vectorize -S < %s 2>&1 | FileCheck %s
; Check that we don't crash.
; CHECK-LABEL: @f
; CHECK: vector.body
target datalayout = "e-m:e-p:32:32:32-a:0-n16:32-i64:64:64-i32:32:32-i16:16:16-i1:8:8-f32:32:32-f64:64:64-v32:32:32-v64:64:64-v512:512:512-v1024:1024:1024-v2048:2048:2048"
; Function Attrs: optsize
define i32 @f(ptr %src) #0 {
entry:
br label %loop
loop:
%g.016 = phi i32 [ 0, %entry ], [ %g.1.lcssa, %loop ]
%iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
%0 = load i8, ptr %src, align 1
%g.1.lcssa = add i32 %g.016, 1
%iv.next = add nsw i32 %iv, 1
%exitcond = icmp eq i32 %iv.next, 1000
br i1 %exitcond, label %exit, label %loop
exit:
ret i32 %g.1.lcssa
}
attributes #0 = { optsize "target-features"="+hvx-length128b" }