; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt < %s -div-rem-pairs -S -mtriple=x86_64-unknown-unknown | FileCheck %s declare void @foo(i32, i32) define void @decompose_illegal_srem_same_block(i32 %a, i32 %b) { ; CHECK-LABEL: @decompose_illegal_srem_same_block( ; CHECK-NEXT: [[DIV:%.*]] = sdiv i32 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: [[T0:%.*]] = mul i32 [[DIV]], [[B]] ; CHECK-NEXT: [[REM_RECOMPOSED:%.*]] = srem i32 [[A]], [[B]] ; CHECK-NEXT: call void @foo(i32 [[REM_RECOMPOSED]], i32 [[DIV]]) ; CHECK-NEXT: ret void ; %div = sdiv i32 %a, %b %t0 = mul i32 %div, %b %rem = sub i32 %a, %t0 call void @foo(i32 %rem, i32 %div) ret void } define void @decompose_illegal_urem_same_block(i32 %a, i32 %b) { ; CHECK-LABEL: @decompose_illegal_urem_same_block( ; CHECK-NEXT: [[DIV:%.*]] = udiv i32 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: [[T0:%.*]] = mul i32 [[DIV]], [[B]] ; CHECK-NEXT: [[REM_RECOMPOSED:%.*]] = urem i32 [[A]], [[B]] ; CHECK-NEXT: call void @foo(i32 [[REM_RECOMPOSED]], i32 [[DIV]]) ; CHECK-NEXT: ret void ; %div = udiv i32 %a, %b %t0 = mul i32 %div, %b %rem = sub i32 %a, %t0 call void @foo(i32 %rem, i32 %div) ret void } ; Recompose and hoist the srem if it's safe and free, otherwise keep as-is.. define i16 @hoist_srem(i16 %a, i16 %b) { ; CHECK-LABEL: @hoist_srem( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[DIV:%.*]] = sdiv i16 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: [[REM_RECOMPOSED:%.*]] = srem i16 [[A]], [[B]] ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i16 [[DIV]], 42 ; CHECK-NEXT: br i1 [[CMP]], label [[IF:%.*]], label [[END:%.*]] ; CHECK: if: ; CHECK-NEXT: [[T0:%.*]] = mul i16 [[DIV]], [[B]] ; CHECK-NEXT: br label [[END]] ; CHECK: end: ; CHECK-NEXT: [[RET:%.*]] = phi i16 [ [[REM_RECOMPOSED]], [[IF]] ], [ 3, [[ENTRY:%.*]] ] ; CHECK-NEXT: ret i16 [[RET]] ; entry: %div = sdiv i16 %a, %b %cmp = icmp eq i16 %div, 42 br i1 %cmp, label %if, label %end if: %t0 = mul i16 %div, %b %rem = sub i16 %a, %t0 br label %end end: %ret = phi i16 [ %rem, %if ], [ 3, %entry ] ret i16 %ret } ; Recompose and hoist the urem if it's safe and free, otherwise keep as-is.. define i8 @hoist_urem(i8 %a, i8 %b) { ; CHECK-LABEL: @hoist_urem( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[DIV:%.*]] = udiv i8 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: [[REM_RECOMPOSED:%.*]] = urem i8 [[A]], [[B]] ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i8 [[DIV]], 42 ; CHECK-NEXT: br i1 [[CMP]], label [[IF:%.*]], label [[END:%.*]] ; CHECK: if: ; CHECK-NEXT: [[T0:%.*]] = mul i8 [[DIV]], [[B]] ; CHECK-NEXT: br label [[END]] ; CHECK: end: ; CHECK-NEXT: [[RET:%.*]] = phi i8 [ [[REM_RECOMPOSED]], [[IF]] ], [ 3, [[ENTRY:%.*]] ] ; CHECK-NEXT: ret i8 [[RET]] ; entry: %div = udiv i8 %a, %b %cmp = icmp eq i8 %div, 42 br i1 %cmp, label %if, label %end if: %t0 = mul i8 %div, %b %rem = sub i8 %a, %t0 br label %end end: %ret = phi i8 [ %rem, %if ], [ 3, %entry ] ret i8 %ret } ; Be careful with RAUW/invalidation if this is a srem-of-srem. define i32 @srem_of_srem_unexpanded(i32 %X, i32 %Y, i32 %Z) { ; CHECK-LABEL: @srem_of_srem_unexpanded( ; CHECK-NEXT: [[T0:%.*]] = mul nsw i32 [[Z:%.*]], [[Y:%.*]] ; CHECK-NEXT: [[T1:%.*]] = sdiv i32 [[X:%.*]], [[T0]] ; CHECK-NEXT: [[T2:%.*]] = mul nsw i32 [[T0]], [[T1]] ; CHECK-NEXT: [[T3:%.*]] = srem i32 [[X]], [[T0]] ; CHECK-NEXT: [[T4:%.*]] = sdiv i32 [[T3]], [[Y]] ; CHECK-NEXT: [[T5:%.*]] = mul nsw i32 [[T4]], [[Y]] ; CHECK-NEXT: [[T6:%.*]] = srem i32 [[T3]], [[Y]] ; CHECK-NEXT: ret i32 [[T6]] ; %t0 = mul nsw i32 %Z, %Y %t1 = sdiv i32 %X, %t0 %t2 = mul nsw i32 %t0, %t1 %t3 = srem i32 %X, %t0 %t4 = sdiv i32 %t3, %Y %t5 = mul nsw i32 %t4, %Y %t6 = srem i32 %t3, %Y ret i32 %t6 } define i32 @srem_of_srem_expanded(i32 %X, i32 %Y, i32 %Z) { ; CHECK-LABEL: @srem_of_srem_expanded( ; CHECK-NEXT: [[T0:%.*]] = mul nsw i32 [[Z:%.*]], [[Y:%.*]] ; CHECK-NEXT: [[T1:%.*]] = sdiv i32 [[X:%.*]], [[T0]] ; CHECK-NEXT: [[T2:%.*]] = mul nsw i32 [[T0]], [[T1]] ; CHECK-NEXT: [[T3_RECOMPOSED:%.*]] = srem i32 [[X]], [[T0]] ; CHECK-NEXT: [[T4:%.*]] = sdiv i32 [[T3_RECOMPOSED]], [[Y]] ; CHECK-NEXT: [[T5:%.*]] = mul nsw i32 [[T4]], [[Y]] ; CHECK-NEXT: [[T6_RECOMPOSED:%.*]] = srem i32 [[T3_RECOMPOSED]], [[Y]] ; CHECK-NEXT: ret i32 [[T6_RECOMPOSED]] ; %t0 = mul nsw i32 %Z, %Y %t1 = sdiv i32 %X, %t0 %t2 = mul nsw i32 %t0, %t1 %t3 = sub nsw i32 %X, %t2 %t4 = sdiv i32 %t3, %Y %t5 = mul nsw i32 %t4, %Y %t6 = sub nsw i32 %t3, %t5 ret i32 %t6 } ; If the target doesn't have a unified div/rem op for the type, keep decomposed rem define i128 @dont_hoist_urem(i128 %a, i128 %b) { ; CHECK-LABEL: @dont_hoist_urem( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[DIV:%.*]] = udiv i128 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i128 [[DIV]], 42 ; CHECK-NEXT: br i1 [[CMP]], label [[IF:%.*]], label [[END:%.*]] ; CHECK: if: ; CHECK-NEXT: [[T0:%.*]] = mul i128 [[DIV]], [[B]] ; CHECK-NEXT: [[REM:%.*]] = sub i128 [[A]], [[T0]] ; CHECK-NEXT: br label [[END]] ; CHECK: end: ; CHECK-NEXT: [[RET:%.*]] = phi i128 [ [[REM]], [[IF]] ], [ 3, [[ENTRY:%.*]] ] ; CHECK-NEXT: ret i128 [[RET]] ; entry: %div = udiv i128 %a, %b %cmp = icmp eq i128 %div, 42 br i1 %cmp, label %if, label %end if: %t0 = mul i128 %div, %b %rem = sub i128 %a, %t0 br label %end end: %ret = phi i128 [ %rem, %if ], [ 3, %entry ] ret i128 %ret } ; Even in expanded form, we can end up with div and rem in different basic ; blocks neither of which dominates each another. define i32 @can_have_divrem_in_mutually_nondominating_bbs(i1 %cmp, i32 %a, i32 %b) { ; CHECK-LABEL: @can_have_divrem_in_mutually_nondominating_bbs( ; CHECK-NEXT: entry: ; CHECK-NEXT: br i1 [[CMP:%.*]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]] ; CHECK: if.then: ; CHECK-NEXT: [[T0:%.*]] = udiv i32 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: [[T1:%.*]] = mul nuw i32 [[T0]], [[B]] ; CHECK-NEXT: [[T2_RECOMPOSED:%.*]] = urem i32 [[A]], [[B]] ; CHECK-NEXT: br label [[END:%.*]] ; CHECK: if.else: ; CHECK-NEXT: [[T3:%.*]] = udiv i32 [[A]], [[B]] ; CHECK-NEXT: br label [[END]] ; CHECK: end: ; CHECK-NEXT: [[RET:%.*]] = phi i32 [ [[T2_RECOMPOSED]], [[IF_THEN]] ], [ [[T3]], [[IF_ELSE]] ] ; CHECK-NEXT: ret i32 [[RET]] ; entry: br i1 %cmp, label %if.then, label %if.else if.then: %t0 = udiv i32 %a, %b %t1 = mul nuw i32 %t0, %b %t2 = sub i32 %a, %t1 br label %end if.else: %t3 = udiv i32 %a, %b br label %end end: %ret = phi i32 [ %t2, %if.then ], [ %t3, %if.else ] ret i32 %ret } ; Test for hoisting a udiv to dominate a urem to allow udivrem. define i64 @remainder_triangle_i64(i64 %a, i64 %b, i64* %rp) { ; CHECK-LABEL: @remainder_triangle_i64( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[CMP:%.*]] = icmp ne i64* [[RP:%.*]], null ; CHECK-NEXT: [[DIV:%.*]] = udiv i64 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: [[REM:%.*]] = urem i64 [[A]], [[B]] ; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[END:%.*]] ; CHECK: if.then: ; CHECK-NEXT: store i64 [[REM]], i64* [[RP]], align 4 ; CHECK-NEXT: br label [[END]] ; CHECK: end: ; CHECK-NEXT: ret i64 [[DIV]] ; entry: %cmp = icmp ne i64* %rp, null br i1 %cmp, label %if.then, label %end if.then: %rem = urem i64 %a, %b store i64 %rem, i64* %rp br label %end end: %div = udiv i64 %a, %b ret i64 %div } ; Test for hoisting a udiv to dominate a urem to allow the urem to be expanded ; into mul+sub. define i128 @remainder_triangle_i128(i128 %a, i128 %b, i128* %rp) { ; CHECK-LABEL: @remainder_triangle_i128( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[CMP:%.*]] = icmp ne i128* [[RP:%.*]], null ; CHECK-NEXT: [[A_FROZEN:%.*]] = freeze i128 [[A:%.*]] ; CHECK-NEXT: [[B_FROZEN:%.*]] = freeze i128 [[B:%.*]] ; CHECK-NEXT: [[DIV:%.*]] = udiv i128 [[A_FROZEN]], [[B_FROZEN]] ; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[END:%.*]] ; CHECK: if.then: ; CHECK-NEXT: [[TMP0:%.*]] = mul i128 [[DIV]], [[B_FROZEN]] ; CHECK-NEXT: [[REM_DECOMPOSED:%.*]] = sub i128 [[A_FROZEN]], [[TMP0]] ; CHECK-NEXT: store i128 [[REM_DECOMPOSED]], i128* [[RP]], align 4 ; CHECK-NEXT: br label [[END]] ; CHECK: end: ; CHECK-NEXT: ret i128 [[DIV]] ; entry: %cmp = icmp ne i128* %rp, null br i1 %cmp, label %if.then, label %end if.then: %rem = urem i128 %a, %b store i128 %rem, i128* %rp br label %end end: %div = udiv i128 %a, %b ret i128 %div } define i64 @remainder_triangle_i64_multiple_rem_edges(i64 %a, i64 %b, i64 %c, i64* %rp) { ; CHECK-LABEL: @remainder_triangle_i64_multiple_rem_edges( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[DIV:%.*]] = udiv i64 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: [[REM:%.*]] = urem i64 [[A]], [[B]] ; CHECK-NEXT: switch i64 [[C:%.*]], label [[SW_DEFAULT:%.*]] [ ; CHECK-NEXT: i64 0, label [[SW_BB:%.*]] ; CHECK-NEXT: i64 2, label [[SW_BB]] ; CHECK-NEXT: ] ; CHECK: sw.bb: ; CHECK-NEXT: store i64 [[REM]], i64* [[RP:%.*]], align 4 ; CHECK-NEXT: br label [[SW_DEFAULT]] ; CHECK: sw.default: ; CHECK-NEXT: ret i64 [[DIV]] ; entry: switch i64 %c, label %sw.default [ i64 0, label %sw.bb i64 2, label %sw.bb ] sw.bb: ; preds = %entry, %entry %rem = urem i64 %a, %b store i64 %rem, i64* %rp br label %sw.default sw.default: ; preds = %entry, %sw.bb %div = udiv i64 %a, %b ret i64 %div } define i64 @remainder_triangle_i64_multiple_div_edges(i64 %a, i64 %b, i64 %c, i64* %rp) { ; CHECK-LABEL: @remainder_triangle_i64_multiple_div_edges( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[DIV:%.*]] = udiv i64 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: [[REM:%.*]] = urem i64 [[A]], [[B]] ; CHECK-NEXT: switch i64 [[C:%.*]], label [[SW_DEFAULT:%.*]] [ ; CHECK-NEXT: i64 0, label [[SW_BB:%.*]] ; CHECK-NEXT: i64 2, label [[SW_BB]] ; CHECK-NEXT: ] ; CHECK: sw.default: ; CHECK-NEXT: store i64 [[REM]], i64* [[RP:%.*]], align 4 ; CHECK-NEXT: br label [[SW_BB]] ; CHECK: sw.bb: ; CHECK-NEXT: ret i64 [[DIV]] ; entry: switch i64 %c, label %sw.default [ i64 0, label %sw.bb i64 2, label %sw.bb ] sw.default: ; preds = %entry, %entry %rem = urem i64 %a, %b store i64 %rem, i64* %rp br label %sw.bb sw.bb: ; preds = %entry, %sw.default %div = udiv i64 %a, %b ret i64 %div } declare void @maythrow() ; Negative test. make sure we don't transform if there are instructions before ; the rem that might throw. define i64 @remainder_triangle_i64_maythrow_rem(i64 %a, i64 %b, i64* %rp) { ; CHECK-LABEL: @remainder_triangle_i64_maythrow_rem( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[CMP:%.*]] = icmp ne i64* [[RP:%.*]], null ; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[END:%.*]] ; CHECK: if.then: ; CHECK-NEXT: call void @maythrow() ; CHECK-NEXT: [[REM:%.*]] = urem i64 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: store i64 [[REM]], i64* [[RP]], align 4 ; CHECK-NEXT: br label [[END]] ; CHECK: end: ; CHECK-NEXT: [[DIV:%.*]] = udiv i64 [[A]], [[B]] ; CHECK-NEXT: ret i64 [[DIV]] ; entry: %cmp = icmp ne i64* %rp, null br i1 %cmp, label %if.then, label %end if.then: call void @maythrow() %rem = urem i64 %a, %b store i64 %rem, i64* %rp br label %end end: %div = udiv i64 %a, %b ret i64 %div } ; Negative test. make sure we don't transform if there are instructions before ; the div that might throw. define i64 @remainder_triangle_i64_maythrow_div(i64 %a, i64 %b, i64* %rp) { ; CHECK-LABEL: @remainder_triangle_i64_maythrow_div( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[CMP:%.*]] = icmp ne i64* [[RP:%.*]], null ; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[END:%.*]] ; CHECK: if.then: ; CHECK-NEXT: [[REM:%.*]] = urem i64 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: store i64 [[REM]], i64* [[RP]], align 4 ; CHECK-NEXT: br label [[END]] ; CHECK: end: ; CHECK-NEXT: call void @maythrow() ; CHECK-NEXT: [[DIV:%.*]] = udiv i64 [[A]], [[B]] ; CHECK-NEXT: ret i64 [[DIV]] ; entry: %cmp = icmp ne i64* %rp, null br i1 %cmp, label %if.then, label %end if.then: %rem = urem i64 %a, %b store i64 %rem, i64* %rp br label %end end: call void @maythrow() %div = udiv i64 %a, %b ret i64 %div } ; Negative test, Make sure we don't transform if there are instructions before ; the rem that might throw. define i128 @remainder_triangle_i128_maythrow_rem(i128 %a, i128 %b, i128* %rp) { ; CHECK-LABEL: @remainder_triangle_i128_maythrow_rem( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[CMP:%.*]] = icmp ne i128* [[RP:%.*]], null ; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[END:%.*]] ; CHECK: if.then: ; CHECK-NEXT: call void @maythrow() ; CHECK-NEXT: [[REM:%.*]] = urem i128 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: store i128 [[REM]], i128* [[RP]], align 4 ; CHECK-NEXT: br label [[END]] ; CHECK: end: ; CHECK-NEXT: [[DIV:%.*]] = udiv i128 [[A]], [[B]] ; CHECK-NEXT: ret i128 [[DIV]] ; entry: %cmp = icmp ne i128* %rp, null br i1 %cmp, label %if.then, label %end if.then: call void @maythrow() %rem = urem i128 %a, %b store i128 %rem, i128* %rp br label %end end: %div = udiv i128 %a, %b ret i128 %div } ; Negative test. Make sure we don't transform if there are instructions before ; the div that might throw. define i128 @remainder_triangle_i128_maythrow_div(i128 %a, i128 %b, i128* %rp) { ; CHECK-LABEL: @remainder_triangle_i128_maythrow_div( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[CMP:%.*]] = icmp ne i128* [[RP:%.*]], null ; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[END:%.*]] ; CHECK: if.then: ; CHECK-NEXT: [[REM:%.*]] = urem i128 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: store i128 [[REM]], i128* [[RP]], align 4 ; CHECK-NEXT: br label [[END]] ; CHECK: end: ; CHECK-NEXT: call void @maythrow() ; CHECK-NEXT: [[DIV:%.*]] = udiv i128 [[A]], [[B]] ; CHECK-NEXT: ret i128 [[DIV]] ; entry: %cmp = icmp ne i128* %rp, null br i1 %cmp, label %if.then, label %end if.then: %rem = urem i128 %a, %b store i128 %rem, i128* %rp br label %end end: call void @maythrow() %div = udiv i128 %a, %b ret i128 %div } ; Negative test. The common predecessor has another successor so we can't hoist ; the udiv to the common predecessor. define i64 @remainder_not_triangle_i32(i64 %a, i64 %b, i64 %c, i64*%rp) { ; CHECK-LABEL: @remainder_not_triangle_i32( ; CHECK-NEXT: entry: ; CHECK-NEXT: switch i64 [[C:%.*]], label [[RETURN:%.*]] [ ; CHECK-NEXT: i64 0, label [[SW_BB:%.*]] ; CHECK-NEXT: i64 1, label [[SW_BB1:%.*]] ; CHECK-NEXT: ] ; CHECK: sw.bb: ; CHECK-NEXT: [[REM:%.*]] = urem i64 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: store i64 [[REM]], i64* [[RP:%.*]], align 4 ; CHECK-NEXT: br label [[SW_BB1]] ; CHECK: sw.bb1: ; CHECK-NEXT: [[DIV:%.*]] = udiv i64 [[A]], [[B]] ; CHECK-NEXT: br label [[RETURN]] ; CHECK: return: ; CHECK-NEXT: [[RETVAL_0:%.*]] = phi i64 [ [[DIV]], [[SW_BB1]] ], [ 0, [[ENTRY:%.*]] ] ; CHECK-NEXT: ret i64 [[RETVAL_0]] ; entry: switch i64 %c, label %return [ i64 0, label %sw.bb i64 1, label %sw.bb1 ] sw.bb: ; preds = %entry %rem = urem i64 %a, %b store i64 %rem, i64* %rp br label %sw.bb1 sw.bb1: ; preds = %entry, %sw.bb %div = udiv i64 %a, %b br label %return return: ; preds = %entry, %sw.bb1 %retval.0 = phi i64 [ %div, %sw.bb1 ], [ 0, %entry ] ret i64 %retval.0 } ; Negative test. The urem block has a successor that isn't udiv. define i64 @remainder_not_triangle_i32_2(i64 %a, i64 %b, i64 %c, i64* %rp) { ; CHECK-LABEL: @remainder_not_triangle_i32_2( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[TOBOOL_NOT:%.*]] = icmp eq i64* [[RP:%.*]], null ; CHECK-NEXT: br i1 [[TOBOOL_NOT]], label [[IF_END3:%.*]], label [[IF_THEN:%.*]] ; CHECK: if.then: ; CHECK-NEXT: [[REM:%.*]] = urem i64 [[A:%.*]], [[B:%.*]] ; CHECK-NEXT: store i64 [[REM]], i64* [[RP]], align 4 ; CHECK-NEXT: [[TOBOOL1_NOT:%.*]] = icmp eq i64 [[C:%.*]], 0 ; CHECK-NEXT: br i1 [[TOBOOL1_NOT]], label [[IF_END3]], label [[RETURN:%.*]] ; CHECK: if.end3: ; CHECK-NEXT: [[DIV:%.*]] = udiv i64 [[A]], [[B]] ; CHECK-NEXT: br label [[RETURN]] ; CHECK: return: ; CHECK-NEXT: [[RETVAL_0:%.*]] = phi i64 [ [[DIV]], [[IF_END3]] ], [ 0, [[IF_THEN]] ] ; CHECK-NEXT: ret i64 [[RETVAL_0]] ; entry: %tobool.not = icmp eq i64* %rp, null br i1 %tobool.not, label %if.end3, label %if.then if.then: ; preds = %entry %rem = urem i64 %a, %b store i64 %rem, i64* %rp %tobool1.not = icmp eq i64 %c, 0 br i1 %tobool1.not, label %if.end3, label %return if.end3: ; preds = %if.then, %entry %div = udiv i64 %a, %b br label %return return: ; preds = %if.then, %if.end3 %retval.0 = phi i64 [ %div, %if.end3 ], [ 0, %if.then ] ret i64 %retval.0 } ; Negative test (this would create invalid IR and crash). ; The div block can't have predecessors other than the rem block ; and the common single pred block (it is reachable from entry here). define i32 @PR51241(i1 %b1, i1 %b2, i32 %t0) { ; CHECK-LABEL: @PR51241( ; CHECK-NEXT: entry: ; CHECK-NEXT: br i1 [[B1:%.*]], label [[DIVBB:%.*]], label [[PREDBB:%.*]] ; CHECK: predbb: ; CHECK-NEXT: br i1 [[B2:%.*]], label [[DIVBB]], label [[REMBB:%.*]] ; CHECK: rembb: ; CHECK-NEXT: [[REM2:%.*]] = srem i32 7, [[T0:%.*]] ; CHECK-NEXT: br label [[DIVBB]] ; CHECK: divbb: ; CHECK-NEXT: [[DIV:%.*]] = sdiv i32 7, [[T0]] ; CHECK-NEXT: ret i32 [[DIV]] ; entry: br i1 %b1, label %divbb, label %predbb predbb: br i1 %b2, label %divbb, label %rembb rembb: %rem2 = srem i32 7, %t0 br label %divbb divbb: %div = sdiv i32 7, %t0 ret i32 %div }