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llvm-mirror/test/Transforms/InstCombine/icmp-mul-zext.ll
Roman Lebedev b0ff9a0dd3 [InstCombine] Fold x & (-1 >> y) == x to x u<= (-1 >> y)
Summary:
https://bugs.llvm.org/show_bug.cgi?id=38123

This pattern will be produced by Implicit Integer Truncation sanitizer,
https://reviews.llvm.org/D48958
https://bugs.llvm.org/show_bug.cgi?id=21530
in unsigned case, therefore it is probably a good idea to improve it.

https://rise4fun.com/Alive/Rny
^ there are more opportunities for folds, i will follow up with them afterwards.

Caveat: this somehow exposes a missing opportunities
in `test/Transforms/InstCombine/icmp-logical.ll`
It seems, the problem is in `foldLogOpOfMaskedICmps()` in `InstCombineAndOrXor.cpp`.
But i'm not quite sure what is wrong, because it calls `getMaskedTypeForICmpPair()`,
which calls `decomposeBitTestICmp()` which should already work for these cases...
As @spatel notes in https://reviews.llvm.org/D49179#1158760,
that code is a rather complex mess, so we'll let it slide.

Reviewers: spatel, craig.topper

Reviewed By: spatel

Subscribers: yamauchi, majnemer, t.p.northover, llvm-commits

Differential Revision: https://reviews.llvm.org/D49179

llvm-svn: 336834
2018-07-11 19:05:04 +00:00

121 lines
4.2 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
define i32 @sterix(i32, i8, i64) {
; CHECK-LABEL: @sterix(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[CONV:%.*]] = zext i32 [[TMP0:%.*]] to i64
; CHECK-NEXT: [[CONV1:%.*]] = sext i8 [[TMP1:%.*]] to i32
; CHECK-NEXT: [[MUL:%.*]] = mul i32 [[CONV1]], 1945964878
; CHECK-NEXT: [[SH_PROM:%.*]] = trunc i64 [[TMP2:%.*]] to i32
; CHECK-NEXT: [[SHR:%.*]] = lshr i32 [[MUL]], [[SH_PROM]]
; CHECK-NEXT: [[CONV2:%.*]] = zext i32 [[SHR]] to i64
; CHECK-NEXT: [[MUL3:%.*]] = mul nuw nsw i64 [[CONV]], [[CONV2]]
; CHECK-NEXT: [[TMP3:%.*]] = icmp ugt i64 [[MUL3]], 4294967295
; CHECK-NEXT: br i1 [[TMP3]], label [[LOR_END:%.*]], label [[LOR_RHS:%.*]]
; CHECK: lor.rhs:
; CHECK-NEXT: [[AND:%.*]] = and i64 [[MUL3]], [[TMP2]]
; CHECK-NEXT: [[CONV4:%.*]] = trunc i64 [[AND]] to i32
; CHECK-NEXT: [[TOBOOL7:%.*]] = icmp eq i32 [[CONV4]], 0
; CHECK-NEXT: [[PHITMP:%.*]] = zext i1 [[TOBOOL7]] to i32
; CHECK-NEXT: br label [[LOR_END]]
; CHECK: lor.end:
; CHECK-NEXT: [[TMP4:%.*]] = phi i32 [ 1, [[ENTRY:%.*]] ], [ [[PHITMP]], [[LOR_RHS]] ]
; CHECK-NEXT: ret i32 [[TMP4]]
;
entry:
%conv = zext i32 %0 to i64
%conv1 = sext i8 %1 to i32
%mul = mul i32 %conv1, 1945964878
%sh_prom = trunc i64 %2 to i32
%shr = lshr i32 %mul, %sh_prom
%conv2 = zext i32 %shr to i64
%mul3 = mul nuw nsw i64 %conv, %conv2
%conv6 = and i64 %mul3, 4294967295
%tobool = icmp ne i64 %conv6, %mul3
br i1 %tobool, label %lor.end, label %lor.rhs
lor.rhs:
%and = and i64 %2, %mul3
%conv4 = trunc i64 %and to i32
%tobool7 = icmp ne i32 %conv4, 0
%lnot = xor i1 %tobool7, true
br label %lor.end
lor.end:
%3 = phi i1 [ true, %entry ], [ %lnot, %lor.rhs ]
%conv8 = zext i1 %3 to i32
ret i32 %conv8
}
; https://bugs.llvm.org/show_bug.cgi?id=33765
@glob = external global i16
define void @PR33765(i8 %beth) {
; CHECK-LABEL: @PR33765(
; CHECK-NEXT: [[CONV:%.*]] = zext i8 [[BETH:%.*]] to i32
; CHECK-NEXT: br i1 false, label [[IF_THEN9:%.*]], label [[IF_THEN9]]
; CHECK: if.then9:
; CHECK-NEXT: [[MUL:%.*]] = mul nuw nsw i32 [[CONV]], [[CONV]]
; CHECK-NEXT: [[TINKY:%.*]] = load i16, i16* @glob, align 2
; CHECK-NEXT: [[TMP1:%.*]] = trunc i32 [[MUL]] to i16
; CHECK-NEXT: [[CONV14:%.*]] = and i16 [[TINKY]], [[TMP1]]
; CHECK-NEXT: store i16 [[CONV14]], i16* @glob, align 2
; CHECK-NEXT: ret void
;
%conv = zext i8 %beth to i32
%mul = mul nuw nsw i32 %conv, %conv
%conv3 = and i32 %mul, 255
%tobool8 = icmp ne i32 %mul, %conv3
br i1 %tobool8, label %if.then9, label %if.then9
if.then9:
%tinky = load i16, i16* @glob
%conv13 = sext i16 %tinky to i32
%and = and i32 %mul, %conv13
%conv14 = trunc i32 %and to i16
store i16 %conv14, i16* @glob
ret void
}
; Repro case for bug involving mutating a list while
; iterating it.
declare i16 @aux(i8)
define i16 @iter_breaker(i16 %a, i16 %b) {
; CHECK-LABEL: @iter_breaker(
; CHECK-NEXT: [[UMUL:%.*]] = call { i16, i1 } @llvm.umul.with.overflow.i16(i16 [[A:%.*]], i16 [[B:%.*]])
; CHECK-NEXT: [[UMUL_VALUE:%.*]] = extractvalue { i16, i1 } [[UMUL]], 0
; CHECK-NEXT: [[DID_OVF:%.*]] = extractvalue { i16, i1 } [[UMUL]], 1
; CHECK-NEXT: br i1 [[DID_OVF]], label [[RET1:%.*]], label [[RET2:%.*]]
; CHECK: ret1:
; CHECK-NEXT: [[TRUNC_REMAIN:%.*]] = trunc i16 [[UMUL_VALUE]] to i8
; CHECK-NEXT: [[VAL:%.*]] = call i16 @aux(i8 [[TRUNC_REMAIN]])
; CHECK-NEXT: ret i16 [[VAL]]
; CHECK: ret2:
; CHECK-NEXT: ret i16 [[UMUL_VALUE]]
;
%a_wide = zext i16 %a to i32
%b_wide = zext i16 %b to i32
%mul_wide = mul i32 %a_wide, %b_wide ; uses of %mul_wide will be iterated
%trunc_remain = trunc i32 %mul_wide to i8 ; this use will be replaced w/ new value
; when iteration visits it, switching
; iteration to the uses of new value
%trunc_unnecessary = trunc i32 %mul_wide to i16 ; uses of %trunc_unnecessary will have
; been updated to uses of new value
%did_ovf = icmp ugt i32 %mul_wide, 65535
br i1 %did_ovf, label %ret1, label %ret2
ret1:
%val = call i16 @aux(i8 %trunc_remain)
ret i16 %val
ret2:
ret i16 %trunc_unnecessary ; crash visiting this use after corrupting iterator
}